Skip to main content
JTO Clinical and Research Reports logoLink to JTO Clinical and Research Reports
. 2022 Feb 22;3(4):100299. doi: 10.1016/j.jtocrr.2022.100299

Comprehensive Analysis of Clinical Logistic and Machine Learning-Based Models for the Evaluation of Pulmonary Nodules

Kai Zhang a, Zihan Wei a,b, Yuntao Nie a, Haifeng Shen a, Xin Wang a,b, Jun Wang a, Fan Yang a, Kezhong Chen a,
PMCID: PMC8980995  PMID: 35392654

Abstract

Introduction

Over the years, multiple models have been developed for the evaluation of pulmonary nodules (PNs). This study aimed to comprehensively investigate clinical models for estimating the malignancy probability in patients with PNs.

Methods

PubMed, EMBASE, Cochrane Library, and Web of Science were searched for studies reporting mathematical models for PN evaluation until March 2020. Eligible models were summarized, and network meta-analysis was performed on externally validated models (PROSPERO database CRD42020154731). The cut-off value of 40% was used to separate patients into high prevalence (HP) and low prevalence (LP), and a subgroup analysis was performed.

Results

A total of 23 original models were proposed in 42 included articles. Age and nodule size were most often used in the models, whereas results of positron emission tomography-computed tomography were used when collected. The Mayo model was validated in 28 studies. The area under the curve values of four most often used models (PKU, Brock, Mayo, VA) were 0.830, 0.785, 0.743, and 0.750, respectively. High-prevalence group (HP) models had better results in HP patients with a pooled sensitivity and specificity of 0.83 (95% confidence interval [CI]: 0.78–0.88) and 0.71 (95% CI: 0.71–0.79), whereas LP models only achieved pooled sensitivity and specificity of 0.70 (95% CI: 0.60–0.79) and 0.70 (95% CI: 0.62–0.77). For LP patients, the pooled sensitivity and specificity decreased from 0.68 (95% CI: 0.57–0.78) and 0.93 (95% CI: 0.87–0.97) to 0.57 (95% CI: 0.21–0.88) and 0.82 (95% CI: 0.65–0.92) when the model changed from LP to HP models. Compared with the clinical models, artificial intelligence-based models have promising preliminary results.

Conclusions

Mathematical models can facilitate the evaluation of lung nodules. Nevertheless, suitable model should be used on appropriate cohorts to achieve an accurate result.

Keywords: Pulmonary nodules, Lung cancer, Prediction model, Network meta-analysis, Machine learning

Introduction

A pulmonary nodule (PN) is defined as an approximately round lesion surrounded by pulmonary parenchyma that is less than 3 cm in diameter. PNs have become increasingly common with the increased use of computed tomography (CT).1, 2, 3 Although most nodules are benign, a proportion of nodules are lung cancers, which is the leading cause of cancer-related death worldwide.4 It is considered that the incidence of cancer in patients with solitary PNs ranges from 3.2% to 4.5%.5,6 Therefore, the main goal for PN management is to identify patients with malignant nodules and administer proper treatment.

Current guidelines for the management of PNs recommend a systematic approach to PN assessment on the basis of clinical and radiographic characteristics.7, 8, 9 The evaluation could be carried out either by experienced clinicians or by mathematical models developed to quantify the probability of malignancy of PNs. For patients with a high risk of malignant PNs, more aggressive interventions such as surgical intervention and CT biopsy are recommended, whereas serial high-resolution CT on a regular basis is recommended for PNs with a low risk of malignancy.10

Over the years, multiple models have been developed for the evaluation of PNs. Nevertheless, owing to various results and a lack of comparison, a consensus has not been made on the diagnostic value of these models. Moreover, with the development of deep learning, artificial intelligence (AI)-based models have been developed, and few articles have compared them with mathematical models. To perform a comprehensive analysis, we reviewed current clinical mathematical models that evaluate the probability of the malignancy of PNs and conducted a network analysis of the diagnostic accuracy of most often used models. We also summarized AI-based models that reported area under the curve11 (AUC) values and compared them with those of the mathematical models.

Materials and Methods

Search Strategy

First, we searched the Medical Subject Headings term database of the National Center for Biotechnology Information for all possible expressions for “lung cancer” and proposed possible expressions for “prediction model.” Then, we used the combination of the expressions to search the PubMed, EMBASE, Cochrane Library, and Web of Science databases up to March 30, 2020, without language limitations. The specific search strategy is listed as follows: (“Clinical Model” or “Clinical Prediction Model” or “Mathematical Model” or “Mathematical Prediction Model” or “Prediction Model” or “Gurney Model” or “Mayo Clinic Model” or “Herder Model” or “VA Model” or “PKU Model” or “Brock Model” or “TREAT Model” or “Bayesian Inference Malignancy Calculator” or “BIMC”) and (“Pulmonary Neoplasms” or “Lung Neoplasm” or “Pulmonary Neoplasm” or “Lung Cancer” or “Pulmonary Cancer” or “Pulmonary Cancers” or “Cancer of the Lung” or “Cancer of Lung” or “Pulmonary Nodule” or “Lung Nodule”).

Titles and abstracts were used to identify papers related to prediction models for the cancer probability assessment of PNs. Full texts were then retrieved to extract data for calculation. This analysis was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.12 The study design was registered in the PROSPERO database (CRD42020154731).

Selection Criteria

Reviews, case studies, editorials, meeting abstracts, and search results that were not related to any search criteria were excluded. All articles that proposed or validated prediction models for cancer probability assessment were included, and further screening was conducted after reading the full-text articles. The exclusion criteria for full-text screening were as follows: (1) the models were not built for predicting the cancer probability of lung nodules; (2) the models were not built with mathematical methods; (3) the models did not take clinical information into consideration; and (4) insufficient data for analysis.

Data Extraction

The following basic information was extracted: first author’s name, year of publication, nation, size of the study, characteristics of the patients included in the study, prevalence of malignancy among the patients, average nodule size, models compared, and the result of comparisons (including the AUC, sensitivity, and specificity of each model compared). For papers that did not report the sensitivity and specificity of the models compared from publicized materials, we sent an e-mail to request the data. Then, we calculated the number of true positives, false negatives, false positives, and true negatives from the data acquired. The AUC values of other PN evaluation methods, including biomarkers, imaging, and physician assessments, were collected in the process for further analysis. Two authors (KZ and ZW) determined the study eligibility and extracted data independently, and any discrepancies between the two authors were resolved by discussion with a third author (KC).

Evaluation of AI-Based Models

Recently, AI-based models were reported to have a fairly good performance in PN evaluation.13,14 Therefore, we also analyzed AI-based models in this study. The AUC values reported by AI-based models were collected, even when these articles were excluded from the major network meta-analysis. Although there has been no article on March 30, 2020, that has compared mathematical models with AI-based models directly, the AUC values of AI-based models were summarized and the trend was analyzed.

Statistical Analysis

All models compared in the studies were included, and the variables used in the models were reviewed. The AUC values were compared by depicting a network plot. Most often used and externally validated models (Brock, Mayo, PKU, VA) were selected for a network meta-analysis; the summary receiver operating characteristic (SROC) curve was plotted with the method proposed by Reitsma et al.15; and the area under the SROC curve (AUSROC) was calculated. Sensitivity and specificity of each model were also pooled using analysis of variance model,16 and diagnostic OR and superiority index were calculated.

In this article, we considered a model as most often used if it has been used in at least five independent cohorts. We noticed that the malignant rate of PNs in the included articles fell into the following two distributions: >40% and <25% (Supplementary Fig. 1); therefore, we used the cut-off value of 40% to separate patients into high prevalence (HP) and low prevalence (LP) and performed a subgroup analysis. Accordingly, models developed using HP nodules (malignant rate >40%) were defined as HP models and models using LP nodules (malignant rate <25%) were defined as LP models. During the analysis, when we encountered studies from the same medical center, we included the study using data from multiple hospitals to prevent duplicated patients.

All analyses were performed by R Software (R version 3.6.1 [2019-07-05], The R Foundation for Statistical Computing, with packages “mada” and “meta4diag”).

Quality of Evidence

Quality Assessment of Diagnostic Accuracy Studies 2 is a tool designed by the Quality Assessment of Diagnostic Accuracy Studies 2 group for the evaluation of the quality of diagnostic accuracy studies.17 The tool comprises the following four domains: patient selection, index test, reference standard, and flow and timing. The methodological quality of the eligible studies was evaluated by this tool by two reviewers (KZ and ZW; Supplementary Table 1).

Results

Our search resulted in 1816 articles, and after assessment, 42 articles were eligible for the study (Fig. 1A). Further searches through the reference list did not reveal additional relevant articles. The status of the data collection is summarized in Supplementary Figure 2.

Figure 1.

Figure 1

Process of study selection and summarization of all variables collected and used in eligible models. (A) PRISMA flow diagram of the study selection process. (B) All variables collected by eligible models. The variables are summarized in a pyramid chart and separated into five levels. Variables with a higher frequency occupy a higher level. The frequency is labeled after the variable names. (C) All variables used by the models. The variables are summarized in a pyramid chart and separated into four levels. Variables with a higher frequency occupy a higher level. The frequency is labeled after the variable names. BMI, body mass index; CEA, carcinoembryonic antigen; CT, computed tomography; CTR, consolidation/tumor ratio; FEV1, forced expiratory volume in the first second; FVC, forced vital capacity; miRNA, microRNA; NSE, neuron-specific enolase; PET, positron emission tomography; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; SCCA, squamous cell carcinoma antigen.

The characteristics of all 42 articles were summarized in Table 1. A total of 23 original models were proposed by these 42 articles (Supplementary Table 2), among which 10 models were externally validated. Most articles used logistic regression to generate a new model, and a few used Bayesian analysis. The variables collected to propose a new model were summarized in Figure 1B, and the variables used in the final model are summarized in Figure 1C. Among the 23 articles that proposed a new model, 22 articles collected data on the age and 21 collected data on the nodule size of the patient, and most of them used these variables in the final model. Nevertheless, although sex was also most often collected, it was seldom used in the final model. Moreover, although there were only a few models that collected the level of uptake or maximum standardized uptake value from positron emission tomography (PET)-CT results, all of them used the result in the final model. The characteristics of the CT images of PNs, including lobulation, calcification, cavitation, border, and pleural retraction sign, were also widely used in the final models.

Table 1.

Characteristics of Eligible Studies

ID Article Country Models Study Population Subgroup Sample Size Prevalence of Malignancy, % Average Nodule Size (mm)
1 Gurney et al.18,a United States Gurneyb Pathologically confirmed SPNs HP 66 67 B 15
M 29
2 Swensen et al.19,a United States Mayob Pathologically confirmed SPNs LP 629 23 B 11.6
M 17.8
3 Herder et al.20,a Netherland Herder,b Mayob SPN without benign calcifications, referred for PET scan HP 106 57
4 Gould et al.21,a United States VAb PNs measured between 7 and 30 mm on CT HP 375 54 17.03
5 Schultz et al.22 United States Mayo,b VAb SPNs confirmed by pathology or 2-y follow-up, age between 39 and 87 y HP 151 44 15
6 Li et al.23,a People’s Republic of China PKU,b Mayo,b VAb Pathologically confirmed SPNs after surgery HP 371 53 19.8
7 Tian et al.24,a People’s Republic of China R Tian et al. SPNs with PET result HP 105 71 12.8
8 McWilliams et al.25,a Canada Brockb PNs from current or former smokers, ages between 50 and 75 y LP 7008 (PanCan) 1 4.3
LP 5021 (BCCA) 1 3.7
9 Xiao et al.26 People’s Republic of China Mayo,b VA,b PKUb Pathologically confirmed SPNs after surgery HP 107 73 19.3
10 Deppen et al.27,a United States TREAT, Mayob Nodules from VUMC cohort and VA cohort HP 492 (VUMC) 72 28
HP 226 (VA) 93 29
11 Zhang et al.28 People’s Republic of China PKU,b Mayo,b VAb Nodule count < 5, mGGO, and solid, no metastasis HP 154 81
12 Al-Ameri et al.29 United Kingdom Herder,a Mayo,a VA,a Brocka PNs confirmed by pathology or 2-y follow-up, without pure GGO HP 244 41
13 Vachani et al.30,a United States A Vachani et al. PNs confirmed by pathology or 2-y follow-up, age >40 y HP 141 55 13
14 Soardi et al.31,a Italy BIMC, Gurneyb SPNs with PET result, without calcification HP 343 58 14.9
15 Yang et al.32,a People’s Republic of China J Yang et al., PKU,b Mayo,b VAb Pathologically confirmed SPNs after surgery HP 252 67 17
16 Zhang et al.33,a People’s Republic of China GMUFH,a Mayo,b VA,b Brock,b PKUb Pathologically confirmed SPNs HP 120 60
17 Chen et al. 201634,a People’s Republic of China J Chen et al., PKU,b Mayo,b VAb Pathologically confirmed SPNs HP 200 68 17.41
HP 89 (Validation) 79 18.91
18 Perandini et al.35 Italy Herder,b BIMC SPNs with PET result, without calcification HP 180 54 17.8
19 Perandini et al.36 Italy Mayo,b Gurney,b PKU,b BIMC Pathologically confirmed SPNs HP 285 55 15.36
20 Soardi et al.37 Italy BIMC, Mayob SPNs from three medical centers HP 200 54 15.89
21 Chen et al.38 People’s Republic of China Mayo,b PKUb Pathologically confirmed PNs after surgery HP 41 76
22 Yang et al.39,a People’s Republic of China Li Yang et al., VA,b Mayob SPN referred to CT-guided biopsy HP 10784 67 18.43
HP 344 (Validation) 69 18.16
23 Tanner et al.40 United States Mayo,b VAb SPN with progression in 60 d, age > 40 y HP 337 47 15.8
24 W Yu (2017)41,a People’s Republic of China W Yu et al. Pathologically confirmed GGO HP 3624 67 1.6
HP 206 (Validation) 70 1.5
25 Lin et al.42 People’s Republic of China Mayob PNs from current or former smokers, ages between 55 and 74 y HP 135 (JPHTCM) 51 15.14
HP 126 (BVAMC) 50 14.365
26 She et al.43,a People’s Republic of China Y She et al., VA,b Mayo,b PKU,b Brockb Pathologically confirmed solid SPNs after surgery HP 8994 67 17.3
HP 899 (Validation) 66 17.3
27 Yang et al.44 Korea Mayo,b VA,b Brock,b Herderb Nodule count < 5, mGGO, and solid, no metastasis HP 242 77 20
28 Kim et al.45 Korea Brock Single subsolid nodules confirmed as AAH or AIS or MIA or IPA HP 101 (GGO) 58 B 11.1
M 14.2
HP 309 (mGGO) 91 B 13.6
M 17.6
29 Wang et al.46,c People’s Republic of China ZU,b Mayo,b VAb SPNs with PET result HP 177 67 18.89
30 Nair et al.47 United States Brock,b Mayo,b VAb Nodules from NLST LP 2196 (Set 1) 9 12.1
LP 6568 (Set 2) 3 7.6
31 Ying et al.48,c People’s Republic of China Ying et al., Mayob Pathologically confirmed microsized SPN (<10 mm) HP 1024 76
HP 10 (Validation) 60
32 Winter et al.49 United States A Winter et al., Brockb Nodules from NLST LP 7879 3 6.89
33 Xiao et al.50,a People’s Republic of China CJFH, Mayo,b VA,b Brock,b PKU,b GMUFHb Pathologically confirmed nonsolid SPNs after surgery HP 362 87 17.6
34 Kim et al.51,a Korea H Kim et al., Brockb Pathologically confirmed subsolid nodules after surgery HP 3214 72 15.7
HP 106 (Validation) 72 15.8
35 Uthoff et al.52 United States Mayo,b VA,b Brock,b PKUb SPNs, age between 40 and 87 y LP 317 22 B 9.2
M 16.3
36 Xi et al.53,a People’s Republic of China K Xi et al. Pathologically confirmed SPNs HP 40 70 B 19
M 25.1
HP 52 75 B 14.0
M 18.3
37 Hammer et al.54 United States Brockb GGO and PSN from NLST LP 434 6
38 Marcus et al.55,a United Kingdom UKLSb Nodules from UKLS trial LP 1013 5
39 Cui et al.56,a People’s Republic of China Mayo,b Brock,b VA b SPNs confirmed by pathology or 2-y follow-up HP 277 73 17
40 Guo et al.57 People’s Republic of China GLCI, Mayo,b PKU,b Herder,b ZU b SPNs with PET result HP 3124 69 18.6
HP 159 (Validation) 80
41 González Maldonado et al.11 Germany Brock,b UKLS,b Mayo,b VA,b PKUb Nodules from LUSI trial LP 3903 2 B 4.0
M 9.4
42 Li et al.58 People’s Republic of China Brock,b Mayo,b VA,b PKUb Pathologically confirmed PNs after surgery HP 496 86

B stands for benign and M stands for malignant.

AAH, atypical adenomatous hyperplasia; AIS, adenocarcinoma in situ; BCCA, British Columbia Cancer Agency; BIMC, Bayesian inference malignancy calculator; BVAMC, Baltimore VA Medical Center; CJFH, China-Japan Friendship Hospital; CT, computed tomography; GGO, ground ground-glass opacity; GLCI, Guangdong Lung Cancer Institute; GMUFH, The First Affiliated Hospital Of Guangzhou Medical University; HP, high prevalence; ID, identification; IPA, invasive pulmonary adenocarcinoma; JPHTCM, Jiangsu Province Hospital of Traditional Chinese Medicine; LP, low prevalence; LUSI, German Lung Cancer Screening Intervention; mGGO, mixed ground-glass opacity; MIA, minimally invasive adenocarcinoma; NLST, National Lung Screening Trial; PanCan, Pan-Canadian Early Detection of Lung Cancer; PET, positron emission tomography; PKU, Peking University; PN, pulmonary nodule; PSN, part part-solid nodule; SPN, solidary pulmonary nodule; TREAT, thoracic research evaluation and treatment; UKLS, UK Lung Cancer Screening; VA, Department of Veterans Affairs; VUMC, Vanderbilt University Medical Center; ZU, Zhejiang University.

a

Models first established in the article.

b

Externally validated model.

For further analysis, we included models that had been validated by at least two external sources for a descriptive analysis of AUC values and seven models qualified for the analysis. A detailed comparison is found in Figure 2A (AUC; Supplementary Table 3). Among the models that were compared more than 10 times, the PKU model had a better AUC value in 26 of 34 of the comparisons. Although only a few articles compared the BIMC model with the other models, the BIMC model yielded an excellent AUC value and wined in all the comparisons. Then, we selected the most often used models for a network meta-analysis. SROC curves were plotted for most often used models (used in at least five independent cohorts) (Fig. 2B), and the PKU model yielded the best AUC. The AUSROC values for the PKU, Brock, VA, and Mayo models were 0.830, 0.785, 0.750, and 0.743, respectively. Diagnostic OR and superior index were also calculated, which revealed similar tendencies (Fig. 2B). The pooled sensitivity and specificity of all externally validated models with diagnostic values provided are compared in Figure 2C, in which most often used models display better and more balanced performance in sensitivity and specificity.

Figure 2.

Figure 2

Comparisons of the AUC values, SROC curves, and diagnostic values among the models. (A) AUC comparison of seven models validated by at least two external sources. Each circular node represents a validated model. The area of the node is proportional to the total number of comparisons in eligible studies. The ratio of the times of better performance to the total number of comparisons is listed inside the node. Each line represents a type of head-to-head comparison, and the color of the line is identical to that of the winning model. The width of the lines is proportional to the number of head-to-head comparisons. (B) SROC curves of models with sufficient external validation (at least five independent cohorts). The solid line depicts the SROC curve plotted by the method proposed by Reitsma et al.,10 and individual observations are marked with round points. The summary point is marked with a triangle point on the SROC curve, and its 95% confidence region is plotted with a dotted line. Different colors are assigned to each model. AUC values are listed in parentheses after the model names in the figure legend. Result of network meta-analysis using ANOVA model is listed below. (C) Comparison of the pooled sensitivity and specificity of the validated models. The value in each cell is defined as the pooled sensitivity or specificity of the model in the same row divided by the pooled sensitivity or specificity of the model in the same column. Cells with the model name are marked in orange, and cells containing the sensitivity and specificity values are marked in yellow and blue, respectively. ANOVA, analysis of variance; AUC, area under the curve; BIMC, Bayesian Inference Malignancy Calculator; DOR, duration of response; SROC, summary receiver operating characteristic.

Because the prevalence of lung cancer differs considerably in HP and LP patients, further analysis was performed after separating patients into the HP group and LP group. The PKU model remained the best model among the four most often used models for HP patients (AUSROC 0.826; Fig. 3A) and had a balanced performance in diagnostic values (Fig. 3B). For LP patients, the Mayo model yielded the best AUSROC (0.928; Fig. 3C) with a smaller confidence region of its summary point. Therefore, according to available data, the Mayo model is suitable for cancer risk prediction in LP patients, with applicable diagnostic value (Fig. 3D).

Figure 3.

Figure 3

Subgroup analysis based on patient characteristics. (A) SROC curves of models with sufficient external validation (at least five independent cohorts) used in HP patients. (B) Comparison of the pooled sensitivity and specificity of the validated models in HP patients. (C) SROC curves of models with sufficient external validation used in LP patients. (D) Comparison of the pooled sensitivity and specificity of the validated models in LP patients. In the SROC plots, the solid line depicts the SROC curve plotted, and individual observations are marked with a round point. The summary point is marked with a triangle point on the SROC curve, and its 95% confidence region is plotted with a dotted line. Different colors are assigned to each model. AUC values are listed in parentheses after the model names in the figure legend. In the comparison of the diagnostic value, the value in each cell is defined as the pooled sensitivity/specificity of the model in the same row divided by the pooled sensitivity/specificity of the model in the same column. Cells with the model name are marked in orange, and cells containing the sensitivity and specificity values are marked in yellow and blue, respectively. AUC, area under the curve; HP, high prevalence; LP, low prevalence; SROC, summary receiver operating characteristic.

A subgroup analysis was conducted to investigate the effect of the prevalence of malignancy in different cohorts on the models. As found in Figure 4, HP models had a better result in predicting the cancer probability of PNs in HP patients, with a pooled sensitivity and specificity of 0.83 (95% confidence interval [CI]: 0.78–0.88; Fig. 4A) and 0.71 (95% CI: 0.63–0.79; Fig. 4B) compared with the LP models, which had a pooled sensitivity and specificity of 0.70 (95% CI: 0.60–0.79; Fig. 4G) and 0.70 (95% CI: 0.62–0.77; Fig. 4H). For LP patients, we observed that the pooled sensitivity and specificity decreased from 0.68 (95% CI: 0.57–0.78; Fig. 4E) and 0.93 (95% CI: 0.87–0.97; Fig. 4F) to 0.57 (95% CI: 0.21–0.88; Fig. 4C) and 0.82 (95% CI: 0.65–0.92; Fig. 4D) when the model was changed from LP models to HP models. Overall, the pooled sensitivity and specificity of the HP models were 0.82 (95% CI: 0.77–0.87; Supplementary Fig. 3A) and 0.72 (95% CI: 0.65–0.79; Supplementary Fig. 3B), and the pooled sensitivity and specificity of the LP models were 0.70 (95% CI: 0.61–0.77; Supplementary Fig. 3C) and 0.76 (95% CI: 0.68–0.83; Supplementary Fig. 3D), respectively.

Figure 4.

Figure 4

Subgroup analysis of the effect of study population on the models. (A) Forest plot of the pooled sensitivity when the HP model is used on HP patients. (B) Forest plot of the pooled specificity when the HP model is used on HP patients. (C) Forest plot of the pooled sensitivity when the HP model is used on LP patients. (D) Forest plot of the pooled specificity when the HP model is used on LP patients. (E) Forest plot of the pooled sensitivity when the LP model is used on LP patients. (F) Forest plot of the pooled specificity when the LP model is used on LP patients. (G) Forest plot of the pooled sensitivity when the LP model is used on HP patients. (H) Forest plot of the pooled specificity when the LP model is used on HP patients. FN, false negative; FP, false positive; HP, high prevalence; LP, low prevalence; TN, true negative; TP, true positive.

To explore the influence of PET-CT on the diagnostic performance of the models, we performed subgroup analysis on the PET-CT results. Models using PET-CT results as a variable had a high pooled sensitivity of 0.88 (95% CI: 0.77–0.95; Supplementary Fig. 4A) compared with 0.73 (95% CI: 0.68–0.77; Supplementary Fig. 4C) for models that did not use PET-CT. Nevertheless, the pooled specificity seemed to be lower in models with PET-CT results of 0.71 (95% CI: 0.49–0.89; Supplementary Fig. 4B) compared with 0.76 (95% CI: 0.71–0.80; Supplementary Fig. 4D) for models without PET-CT.

Among some of the included articles, the diagnostic value of the model was also compared with that of various biomarkers, imaging methods, and physician assessment. The AUC values of each method were collected and analyzed. The average AUC value of the models was higher than that of the other methods, although no significant difference was observed (Supplementary Fig. 5A).

When evaluating AI-based models, 11 articles were included, and five of them were developed using HP patients whereas others were developed using LP patients from screening projects. The AUC values of the AI-based models were compared with those of the models, biomarkers, imaging, and physicians (Supplementary Fig. 5B). In recent 5 years, the AUC of the AI-based models had raised from an average of 0.831 (±0.071) in 2017 to 0.919 in 2020, whereas the AUC of the mathematical models seems to bear a better robustness. Further regression of the AUC values of the AI-based models revealed that the AUC values of the AI-based models increased with the development of AI throughout the years (p = 0.074; Supplementary Fig. 5C), whereas mathematical models did not. Though the development of AI-based models seemed not statistically different, the trend can also be validated by studies in the same data set.59 Nevertheless, this might indicate that the performance of well-trained AI models might exceed that of the current methods in PN evaluation in the future. External validation is still needed for the AI-based models.

Discussion

With the increasing use of CT in lung cancer screening, it has become increasingly considerable to estimate the cancer probability accurately during the management of PNs for both inpatients in the surgical department and outpatients who participate in CT screening. In view of this, we summarized all clinical mathematical models for the evaluation of PNs and conducted a network meta-analysis for the first time. To ensure objectivity and fairness, we contacted the authors of all published articles that lacked the desired data (Supplementary Fig. 2).

As the first probability model that used logistic regression, the Mayo model has become the most externally validated among all models (Table 2). It is built from a retrospective data set of 419 patients with more than 20 variables taken into consideration. Owing to the large number of variables collected, the Mayo model has remained a rather accurate model throughout the years. Among most often used models, the PKU model yields the best AUC. It is the first model built with the Chinese population and is the only eastern population model that has been validated with the western population. Compared with the Mayo model, all patients enrolled in the PKU model had a defined pathologic diagnosis and comprehensive radiographical characteristics.

Table 2.

Summarization of Highlights of Different Models

First Established Model Gurney et al.1 (First Model Using Bayesian Analysis) Mayo (1997) (First Model Using Logistic Regression)
Model with the largest sample size Brock (7008 nodules)
Most verified model Mayo (compared in 28 articles)
Best performing model BIMC (among all validated models) PKUPH (among all models validated by ≥5 cohorts)
Model with the most variables collected Mayo (23 variables)
Models with external validation when established Brock, TREAT
Models compared with physicians Gurney, Mayo, VA, Brock
Models with a nomogram or a web calculator Y She et al., Herder, BIMC, GLCI
Sample with highest and lowest cancer rates Highest: TREAT Lowest: Brock
Models with highest and lowest cut-off values (mentioned in original article) Highest: CJFH (0.794) Lowest: W Yu et al. (0.3649)
Model that has been compared with AI models Brock (compared with AI based on CNN in David Baldwin et al., AI had better result in HP patients)

AI, artificial intelligence; BIMC, Bayesian inference malignancy calculator; CJFH, China-Japan Friendship Hospital; CNN, convolutional neural networks; GLCI, Guangdong Lung Cancer Institute; HP, high prevalence; PKUPH, Peking University People’s Hospital; TREAT, thoracic research evaluation and treatment; VA, Department of Veterans Affairs.

Owing to the variation in research cohort, models proposed in past studies can be separated into two categories. The first category is models on the basis of the population who underwent lung cancer screening. The characteristic of this type of model is that benign nodules account for most of the PNs enrolled in model development. The other category is models on the basis of patients treated in clinic or surgery. The characteristic of this type of model is that eligible patients for model development have already undergone preliminary screening, during which only people with HP nodules are admitted for further treatment. Therefore, the malignant rate differs considerably in these two categories. As found in Supplementary Figure 1, the malignant rate in the first category is below 25%, whereas in the other category, this rate is usually above 40%. As a result, the effectiveness of the models established by different populations differs, and it is not fair to compare different models using the same population. The original cut-off value may no longer be suitable if the models are not used on the targeted populations (Supplementary Table 4). Nevertheless, previous studies often failed to compare these two types of models in different populations. For the first time, we distinguished between the HP group and the LP group on the basis of the probability of malignancy. Furthermore, subgroup analysis revealed that regardless of the HP model or LP model, sensitivity and specificity dropped as long as they were not used on the targeted populations. Thus, we recommend that the more suitable model should be used for the appropriate cohorts to achieve the best result.

Nevertheless, there are few limitations in our analysis. First, although AUC is the most important indicator of model accuracy, AUC alone cannot comprehensively describe a model. For example, performance calibration is also important for clinical use of a model, but not enough data were provided for a subgroup analysis in our research. Moreover, most of the values of sensitivity and specificity are acquired by Youden index. Although the Youden index provides the highest overall accuracy, in some cases, one would prefer additional sensitivity at the loss of some specificity or vice versa, which makes the Youden index not suitable for some clinical scenario. Another limitation lies in the cohort included in the analysis, as the prevalence was much higher than some recent screening cohorts, which may lead to bias when used in these cohorts. Moreover, owing to the lack of data, some results bear a large 95% CI, which makes the conclusions not so determinate, and more cohorts are needed (especially outpatient cohorts) for further validation to achieve a more accurate result in the comparisons of models.

It is noteworthy that PET-CT results are included in the final model as long as they are collected, suggesting that positive PET-CT results are a strong indicator for malignancy. Nevertheless, problems remain for PEC-CT, which are as follows: (1) although PET-CT improves the sensitivity, it may also have a false-positive result for inflammation, tuberculosis, and so on; (2) PET-CT is only recommended for solid nodules instead of ground-glass opacities, making the clinical application of the model restricted to solid nodules; and (3) because of the high cost of PET-CT in some countries, the result is not available in all situations, which is also a limitation for clinical application. These limitations are also the reason why PET-CT is viewed as a preclinical evaluation instead of as a standard procedure for lung cancer diagnosis by most researchers.

A few studies evaluated both models and physician assessments. We analyzed these articles and found that the models have a better result than the clinicians, but there were no significant differences (Supplementary Fig. 5A). It is important to note that in these studies, the physicians were experienced and familiar with the models, which might lead to bias. The greatest strength of the models is that they are stable and easy to widely use. In fact, many doctors in small hospitals or rural hospitals do not have sufficient experience in differentiating benign and malignant PNs. We believe that the models are more accurate than these doctors and thus are of value in clinical application. Another advantage of prediction models would be the objectivity. Physician judgment of the same nodule may vary in different scenarios (different environment, emotional state, physical state, etc.), but the prediction result of a model stays the same, making the model’s assessment much more objective and repeatable. We believe that a better model could aid more in clinical work both for experienced clinicians and younger clinicians and could make a more objective conclusion for patients.

Although there are guidelines recommending using models for PN evaluation, the clinical applications of these prediction models are still limited. An important reason for this is that the mathematical formula is not practical for clinical practice, and it is time consuming to calculate the cancer probability of each nodule encountered. In fact, models can be exported to an easy-to-read form, such as nomograms or web calculators. Especially for the latter, with only the clinical information of the patient as input, the malignant risk of a PN can be conveniently calculated in less than 10 seconds. Nevertheless, only a few models had a web version built at the time of publication. An example is given in Supplementary Figure 6, illustrating the typical calculation process with the mathematical formula, nomogram, and web calculator, revealing that the nomogram and web calculator are clearer and easier for clinical use. In addition, decision-making in clinical practice cannot exclusively depend on the risk probability of the model. On one hand, clinical treatment is also affected by many other factors, such as patient preference. On the other hand, the model is merely a generally comprehensive analysis. Owing to the heterogeneity of patients’ nodules, the model might not be accurate for individuals. The role of the model is to only provide a relatively reliable reference for clinical judgment, but it cannot completely replace the clinicians to make the final decision.

In recent years, AI has started to play a role in the cancer risk prediction of PNs, and AI-based prediction models have been compared with traditional mathematical models. Therefore, we summarized all reported computer-aided diagnosis (CADx) systems with their AUC values (Supplementary Table 5). As we were preparing this meta-analysis, Baldwin et al.10 reported the result of a comparison of CADx system and the Brock model, revealing that the CADx achieved a better AUC. Nevertheless, the analysis was conducted on a HP cohort, whereas the accuracy of the Brock model might be underestimated as it was developed on the basis of LP cohorts. According to our result, it is more equitable in future studies to use identical background models for the comparison to evaluate whether such AI models have transcended the mathematical model. Despite the outstanding AUC values reported, problems remain for the CADx systems. First, because researchers seldom provide a model for external validation, there is a lack of prospective studies to validate its efficacy in different populations. In addition, because of the lack of clinical information in open data sets, all current CADx systems can only predict malignant risk with radiographical characteristics and cannot take clinical features into consideration as clinicians or models do. In some cases, such as the evaluation of PNs in patients with a history of cancer, the judgment of CADx may bear notable bias. Therefore, further exploration and improvement are still needed for the CADx systems. Mathematical models and machine learning models are both statistical models in some ways. Deep learning, the typical method used in nodule detection, uses simple functions such as the sigmoid function or the rectified linear unit function as the activation function inside individual neurons. The utilization of large amounts of neurons results in a multilayer network, whereas its purpose is still to separate nodules into benign and malignant nodules. Therefore, it is safe to say that this network places individual observations into a higher dimension and finds a function to fit the observations, which is basically the idea behind mathematical models. In fact, the discovery of new regression functions is how humans fit the observations, whereas the training of neural networks is how machines fit them. In some ways, AI is an extension of mathematical models. According to our result, it is possible that with the continuous training of AI, its diagnostic efficiency may be further improved, and eventually exceed the prediction accuracy of mathematical models in the future. Nevertheless, so far, there is no enough evidence to prove that the accuracy of AI can be improved in the future and more comparisons between AI-based models and mathematical models in the same population are still needed. Therefore, for now, the widely validated mathematical models are still the most convenient and relatively accurate way to assist PN management.

In conclusion, we systematically reviewed and analyzed a variety of prediction models of PNs. The Mayo model is the most widely used and validated model, whereas the PKU model yields the best AUC among the most often used models. Because of the discrepant development cohorts among the models, it is vital that the most suitable model is used on the appropriate cohorts, and mixing models might lead to decreased accuracy. Nomograms or web calculators are intuitive and preferred by clinicians, but their clinical application needs to be further investigated.

CRediT Authorship Contribution Statement

Kai Zhang: Methodology, Formal analysis, Data curation, Writing - original draft, Writing - review & editing.

Zihan Wei: Methodology, Formal analysis, Data curation, Writing - original draft.

Yuntao Nie: Formal analysis, Data curation, Validation.

Haifeng Shen: Formal analysis, Data curation.

Xin Wang: Data curation.

Jun Wang: Conceptualization, Supervision.

Fan Yang: Methodology, Supervision.

Kezhong Chen: Conceptualization, Methodology, Supervision, Writing - review & editing.

Acknowledgments

This study was supported by the National Natural Science Funds (grant number 82072566) and Peking University People's Hospital Research and Development Funds (grant number RS2019-01). Special thanks to Otto Hoekstra, Mark Hammer, Juan Yang, Fei Xiao, Chang Min Park, Simon Parandini, Rudolf Kaaks, Sandra González Maldonado, Chang Chen, and Yunlang She, who kindly replied to our e-mails on data inquiry.

Footnotes

Drs. Zhang and Wei contributed equally to this work.

Both Drs. J. Wang and Yang are senior authors.

Disclosure: The authors declare no conflict of interest.

Cite this article as: Zhang K, Wei Z, Nie Y, et al. Comprehensive analysis of clinical logistic and machine learning-based models for the evaluation of pulmonary nodules. JTO Clin Res Rep. 2022;3:100299.

Note: To access the supplementary material accompanying this article, visit the online version of the JTO Clinical and Research Reports at www.jtocrr.org and at https://doi.org/10.1016/j.jtocrr.2022.100299.

Supplementary Data

Supplementary Figure 1.

Supplementary Figure 1

Supplementary Figure 2.

Supplementary Figure 2

Supplementary Figure 3.

Supplementary Figure 3

Supplementary Figure 4.

Supplementary Figure 4

Supplementary Figure 5.

Supplementary Figure 5

Supplementary Figure 6.

Supplementary Figure 6

Supplementary Tables 1–5
mmc1.docx (52.9KB, docx)

References

  • 1.de Koning H.J., van der Aalst C.M., de Jong P.A., et al. Reduced lung-cancer mortality with volume CT screening in a randomized trial. N Engl J Med. 2020;382:503–513. doi: 10.1056/NEJMoa1911793. [DOI] [PubMed] [Google Scholar]
  • 2.Field J.K., Duffy S.W., Baldwin D.R., et al. The UK Lung Cancer Screening Trial: a pilot randomised controlled trial of low-dose computed tomography screening for the early detection of lung cancer. Health Technol Assess. 2016;20:1–146. doi: 10.3310/hta20400. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.National Lung Screening Trial Research Team. Aberle D.R., Adams A.M., et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med. 2011;365:395–409. doi: 10.1056/NEJMoa1102873. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Siegel R.L., Miller K.D., Jemal A. Cancer statistics, 2018. CA Cancer J Clin. 2018;68:7–30. doi: 10.3322/caac.21442. [DOI] [PubMed] [Google Scholar]
  • 5.Yousaf-Khan U., van der Aalst C., de Jong P.A., et al. Final screening round of the NELSON lung cancer screening trial: the effect of a 2.5-year screening interval. Thorax. 2017;72:48–56. doi: 10.1136/thoraxjnl-2016-208655. [DOI] [PubMed] [Google Scholar]
  • 6.Infante M., Sestini S., Galeone C., et al. Lung cancer screening with low-dose spiral computed tomography: evidence from a pooled analysis of two Italian randomized trials. Eur J Cancer Prev. 2017;26:324–329. doi: 10.1097/CEJ.0000000000000264. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Callister M.E., Baldwin D.R., Akram A.R., et al. British Thoracic Society guidelines for the investigation and management of pulmonary nodules. Thorax. 2015;70(suppl 2):ii1–ii54. doi: 10.1136/thoraxjnl-2015-207168. [DOI] [PubMed] [Google Scholar]
  • 8.Gould M.K., Donington J., Lynch W.R., et al. Evaluation of individuals with pulmonary nodules: when is it lung cancer? Diagnosis and management of lung cancer. 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2013;143(suppl):e93S–e120S. doi: 10.1378/chest.12-2351. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.MacMahon H., Naidich D.P., Goo J.M., et al. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology. 2017;284:228–243. doi: 10.1148/radiol.2017161659. [DOI] [PubMed] [Google Scholar]
  • 10.Ost D., Fein A.M., Feinsilver S.H. Clinical practice. The solitary pulmonary nodule. N Engl J Med. 2003;348:2535–2542. doi: 10.1056/NEJMcp012290. [DOI] [PubMed] [Google Scholar]
  • 11.González Maldonado S., Delorme S., Hüsing A., et al. Evaluation of prediction models for identifying malignancy in pulmonary nodules detected via low-dose computed tomography. JAMA Netw Open. 2020;3 doi: 10.1001/jamanetworkopen.2019.21221. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Moher D., Liberati A., Tetzlaff J., Altman D.G., PRISMA Group Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6 [PMC free article] [PubMed] [Google Scholar]
  • 13.Baldwin D.R., Gustafson J., Pickup L., et al. External validation of a convolutional neural network artificial intelligence tool to predict malignancy in pulmonary nodules. Thorax. 2020;75:306–312. doi: 10.1136/thoraxjnl-2019-214104. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Reitsma J.B., Glas A.S., Rutjes A.W., Scholten R.J., Bossuyt P.M., Zwinderman A.H. Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. J Clin Epidemiol. 2005;58:982–990. doi: 10.1016/j.jclinepi.2005.02.022. [DOI] [PubMed] [Google Scholar]
  • 15.Chen K., Nie Y., Park S., et al. Development and validation of machine learning-based model for the prediction of malignancy in multiple pulmonary nodules: analysis from multicentric cohorts. Clin Cancer Res. 2021;27:2255–2265. doi: 10.1158/1078-0432.CCR-20-4007. [DOI] [PubMed] [Google Scholar]
  • 16.Nyaga V.N., Aerts M., Arbyn M. ANOVA model for network meta-analysis of diagnostic test accuracy data. Stat Methods Med Res. 2018;27:1766–1784. doi: 10.1177/0962280216669182. [DOI] [PubMed] [Google Scholar]
  • 17.Whiting P.F., Rutjes A.W., Westwood M.E., et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155:529–536. doi: 10.7326/0003-4819-155-8-201110180-00009. [DOI] [PubMed] [Google Scholar]
  • 18.Gurney J.W., Lyddon D.M., McKay J.A. Determining the likelihood of malignancy in solitary pulmonary nodules with Bayesian analysis. Part II. Application. Radiology. 1993;186:415–422. doi: 10.1148/radiology.186.2.8421744. [DOI] [PubMed] [Google Scholar]
  • 19.Swensen S.J., Silverstein M.D., Ilstrup D.M., Schleck C.D., Edell E.S. The probability of malignancy in solitary pulmonary nodules. Application to small radiologically indeterminate nodules. Arch Intern Med. 1997;157:849–855. [PubMed] [Google Scholar]
  • 20.Herder G.J., van Tinteren H., Golding R.P., et al. Clinical prediction model to characterize pulmonary nodules: validation and added value of 18F-fluorodeoxyglucose positron emission tomography. Chest. 2005;128:2490–2496. doi: 10.1378/chest.128.4.2490. [DOI] [PubMed] [Google Scholar]
  • 21.Gould M.K., Ananth L., Barnett P.G., Veterans Affairs SNAP Cooperative Study Group A clinical model to estimate the pretest probability of lung cancer in patients with solitary pulmonary nodules. Chest. 2007;131:383–388. doi: 10.1378/chest.06-1261. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Schultz E.M., Sanders G.D., Trotter P.R., et al. Validation of two models to estimate the probability of malignancy in patients with solitary pulmonary nodules. Thorax. 2008;63:335–341. doi: 10.1136/thx.2007.084731. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Li Y., Chen K.Z., Wang J. Development and validation of a clinical prediction model to estimate the probability of malignancy in solitary pulmonary nodules in Chinese people. Clin Lung Cancer. 2011;12:313–319. doi: 10.1016/j.cllc.2011.06.005. [DOI] [PubMed] [Google Scholar]
  • 24.Tian R., Su M.G., Tian Y., Li F.L., Kuang A.R. [Development of a predicting model to estimate the probability of malignancy of solitary pulmonary nodules] Sichuan Da Xue Xue Bao Yi Xue Ban. 2012;43:404–408. [PubMed] [Google Scholar]
  • 25.McWilliams A., Tammemagi M.C., Mayo J.R., et al. Probability of cancer in pulmonary nodules detected on first screening CT. N Engl J Med. 2013;369:910–919. doi: 10.1056/NEJMoa1214726. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Xiao F., Liu D., Guo Y., et al. Novel and convenient method to evaluate the character of solitary pulmonary nodule-comparison of three mathematical prediction models and further stratification of risk factors. PLoS One. 2013;8 doi: 10.1371/journal.pone.0078271. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Deppen S.A., Blume J.D., Aldrich M.C., et al. Predicting lung cancer prior to surgical resection in patients with lung nodules. J Thorac Oncol. 2014;9:1477–1484. doi: 10.1097/JTO.0000000000000287. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Zhang X., Yan H.H., Lin J.T., et al. Comparison of three mathematical prediction models in patients with a solitary pulmonary nodule. Chin J Cancer Res. 2014;26:647–652. doi: 10.3978/j.issn.1000-9604.2014.11.02. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Al-Ameri A., Malhotra P., Thygesen H., et al. Risk of malignancy in pulmonary nodules: A validation study of four prediction models. Lung Cancer. 2015;89:27–30. doi: 10.1016/j.lungcan.2015.03.018. [DOI] [PubMed] [Google Scholar]
  • 30.Vachani A., Pass H.I., Rom W.N., et al. Validation of a multiprotein plasma classifier to identify benign lung nodules. J Thorac Oncol. 2015;10:629–637. doi: 10.1097/JTO.0000000000000447. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Soardi G.A., Perandini S., Motton M., Montemezzi S. Assessing probability of malignancy in solid solitary pulmonary nodules with a new Bayesian calculator: improving diagnostic accuracy by means of expanded and updated features. Eur Radiol. 2015;25:155–162. doi: 10.1007/s00330-014-3396-2. [DOI] [PubMed] [Google Scholar]
  • 32.Yang J., Xue-Li S., Guo-Xiang L., Qiang L., Yi-Ping H., Han Y. Establishment and validation of mathematics model for differentiating benign and malignant solitary pulmonary nodules. Acad J Second Mil Med Univ. 2015;36:407–412. [Google Scholar]
  • 33.Zhang M., Zhuo N., Guo Z., et al. Establishment of a mathematic model for predicting malignancy in solitary pulmonary nodules. J Thorac Dis. 2015;7:1833–1841. doi: 10.3978/j.issn.2072-1439.2015.10.56. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Chen J., Xiao-Dan Y., Jian-Ding Y., Zheng-Rong Z. Establishment and verification of a mathematical model for predicting malignancy of solitary pulmonary nodules. Chin Comput Med Imaging. 2016;22:573–577. [Google Scholar]
  • 35.Perandini S., Soardi G.A., Larici A.R., et al. Multicenter external validation of two malignancy risk prediction models in patients undergoing 18F-FDG-PET for solitary pulmonary nodule evaluation. Eur Radiol. 2017;27:2042–2046. doi: 10.1007/s00330-016-4580-3. [DOI] [PubMed] [Google Scholar]
  • 36.Perandini S., Soardi G.A., Motton M., Rossi A., Signorini M., Montemezzi S. Solid pulmonary nodule risk assessment and decision analysis: comparison of four prediction models in 285 cases. Eur Radiol. 2016;26:3071–3076. doi: 10.1007/s00330-015-4138-9. [DOI] [PubMed] [Google Scholar]
  • 37.Soardi G.A., Perandini S., Larici A.R., et al. Multicentre external validation of the BIMC model for solid solitary pulmonary nodule malignancy prediction. Eur Radiol. 2017;27:1929–1933. doi: 10.1007/s00330-016-4538-5. [DOI] [PubMed] [Google Scholar]
  • 38.Chen K., Zhang J., Guan T., et al. Comparison of plasma to tissue DNA mutations in surgical patients with non-small cell lung cancer. J Thorac Cardiovasc Surg. 2017;154:1123–1131.e2. doi: 10.1016/j.jtcvs.2017.04.073. [DOI] [PubMed] [Google Scholar]
  • 39.Yang L., Zhang Q., Bai L., et al. Assessment of the cancer risk factors of solitary pulmonary nodules. Oncotarget. 2017;8:29318–29327. doi: 10.18632/oncotarget.16426. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Tanner N.T., Porter A., Gould M.K., Li X.J., Vachani A., Silvestri G.A. Physician assessment of pretest probability of malignancy and adherence with guidelines for pulmonary nodule evaluation. Chest. 2017;152:263–270. doi: 10.1016/j.chest.2017.01.018. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41.Wei Y., Tianxiang C., Liyun X., Zhaoyu W., Hanbo C., Yongkui Z. Establishment of the diagnostic model in solitary pulmonary nodule appearing as ground-glass nodule. Chin J Med Imaging. 2017;25:435–440. [Google Scholar]
  • 42.Lin Y., Leng Q., Jiang Z., et al. A classifier integrating plasma biomarkers and radiological characteristics for distinguishing malignant from benign pulmonary nodules. Int J Cancer. 2017;141:1240–1248. doi: 10.1002/ijc.30822. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43.She Y., Zhao L., Dai C., et al. Development and validation of a nomogram to estimate the pretest probability of cancer in Chinese patients with solid solitary pulmonary nodules: a multi-institutional study. J Surg Oncol. 2017;116:756–762. doi: 10.1002/jso.24704. [DOI] [PubMed] [Google Scholar]
  • 44.Yang B., Jhun B.W., Shin S.H., et al. Comparison of four models predicting the malignancy of pulmonary nodules: A single-center study of Korean adults. PLoS One. 2018;13 doi: 10.1371/journal.pone.0201242. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 45.Kim H., Park C.M., Jeon S., et al. Validation of prediction models for risk stratification of incidentally detected pulmonary subsolid nodules: a retrospective cohort study in a Korean tertiary medical centre. BMJ Open. 2018;8 doi: 10.1136/bmjopen-2017-019996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 46.Wang L., Chen Y., Tang K., Lin J., Zhang H. The value of 18F-FDG PET/CT Mathematical Prediction Model in Diagnosis of Solitary Pulmonary Nodules. BioMed Res Int. 2018;2018:9453967. doi: 10.1155/2018/9453967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 47.Nair V.S., Sundaram V., Desai M., Gould M.K. Accuracy of models to identify lung nodule cancer risk in the National Lung Screening Trial. Am J Respir Crit Care Med. 2018;197:1220–1223. doi: 10.1164/rccm.201708-1632LE. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 48.Ying Z.H.U., Panfeng X.U., Yake Y.A.O., Jianfang P., Jianying Z.H.O.U. Independent predictors and prediction model of malignant micro-sized solitary pulmonary nodules. Chin J Clin Oncol. 2018;45:497–502. [Google Scholar]
  • 49.Winter A., Aberle D.R., Hsu W. External validation and recalibration of the Brock model to predict probability of cancer in pulmonary nodules using NLST data. Thorax. 2019;74:551–563. doi: 10.1136/thoraxjnl-2018-212413. [DOI] [PubMed] [Google Scholar]
  • 50.Xiao F., Yu Q., Zhang Z., Liu D., Liang C. [Establishment and verification of A novel predictive model of Malignancy for Non-solid Pulmonary Nodules] Zhongguo Fei Ai Za Zhi. 2019;22:26–33. doi: 10.3779/j.issn.1009-3419.2019.01.06. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 51.Kim H., Goo J.M., Park C.M. A simple prediction model using size measures for discrimination of invasive adenocarcinomas among incidental pulmonary subsolid nodules considered for resection. Eur Radiol. 2019;29:1674–1683. doi: 10.1007/s00330-018-5739-x. [DOI] [PubMed] [Google Scholar]
  • 52.Uthoff J., Koehn N., Larson J., et al. Post-imaging pulmonary nodule mathematical prediction models: are they clinically relevant? Eur Radiol. 2019;29:5367–5377. doi: 10.1007/s00330-019-06168-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 53.Xi K., Wang W., Wen Y., et al. Combining plasma miRNAs and computed tomography features to differentiate the nature of pulmonary nodules. Front Oncol. 2019;9:975. doi: 10.3389/fonc.2019.00975. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 54.Hammer M.M., Palazzo L.L., Kong C.Y., Hunsaker A.R. Cancer risk in subsolid nodules in the National Lung Screening Trial. Radiology. 2019;293:441–448. doi: 10.1148/radiol.2019190905. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 55.Marcus M.W., Duffy S.W., Devaraj A., et al. Probability of cancer in lung nodules using sequential volumetric screening up to 12 months: the UKLS trial. Thorax. 2019;74:761–767. doi: 10.1136/thoraxjnl-2018-212263. [DOI] [PubMed] [Google Scholar]
  • 56.Cui X., Heuvelmans M.A., Han D., et al. Comparison of Veterans Affairs, Mayo, Brock classification models and radiologist diagnosis for classifying the malignancy of pulmonary nodules in Chinese clinical population. Transl Lung Cancer Res. 2019;8:605–613. doi: 10.21037/tlcr.2019.09.17. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 57.Guo H.Y., Lin J.T., Huang H.H., et al. Development and validation of a 18F-FDG PET/CT-based clinical prediction model for estimating malignancy in solid pulmonary nodules based on a population with high prevalence of malignancy. Clin Lung Cancer. 2020;21:47–55. doi: 10.1016/j.cllc.2019.07.014. [DOI] [PubMed] [Google Scholar]
  • 58.Li Y., Hu H., Wu Z., et al. Evaluation of models for predicting the probability of malignancy in patients with pulmonary nodules. Biosci Rep. 2020;40 doi: 10.1042/BSR20193875. BSR20193875. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 59.Schreuder A., Scholten E.T., van Ginneken B., Jacobs C. Artificial intelligence for detection and characterization of pulmonary nodules in lung cancer CT screening: ready for practice? Transl Lung Cancer Res. 2021;10:2378–2388. doi: 10.21037/tlcr-2020-lcs-06. [DOI] [PMC free article] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplementary Tables 1–5
mmc1.docx (52.9KB, docx)

Articles from JTO Clinical and Research Reports are provided here courtesy of Elsevier

RESOURCES