Abstract
Background
Thyroid cancer incidence is rising worldwide, yet comprehensive longitudinal data linking contemporary demographic, pathological, and surgical trends to recurrence risk remain scarce.
Methods
A retrospective analysis was performed on 9504 thyroid cancer patients from 2008 to 2023. Based on the year of treatment, patients were categorized into 3 groups for comparative assessment. Demographic features, clinical pathological characteristics, surgical approaches, and prognostic outcomes were evaluated.
Results
Over the 16-year period, the annual number of new thyroid cancer cases demonstrated a consistent upward trend, with a growing proportion detected through routine health screenings. The male-to-female ratio was 1:2.76, with a gradual increase in male patients. The peak age at diagnosis remained between 30 and 60 years, while the proportion of juvenile patients declined steadily. Papillary thyroid carcinoma constituted the predominant histologic type. Surgical management shifted toward more conservative approaches. Although tumor size decreased over time, the incidence of multifocal lesions and the BRAF V600E mutation rate rose. Lymph node metastasis rates also increased, particularly in patients with central region metastases and metastases in ≤5 lymph nodes. Multivariate analysis identified age, tumor size, and number of metastatic lymph nodes as independent risk factors for recurrence in papillary thyroid carcinoma. Patients older than 55 years, those with larger lesions, or those with more lymph node metastases exhibited a significantly elevated recurrence risk.
Conclusion
Although thyroid cancers are being detected at earlier stages and smaller sizes, the burdens of molecular, multifocal, and lymph node disease are increasing. Age, tumor size, and nodal metastatic load constitute robust independent predictors of recurrence in papillary thyroid carcinoma, informing risk-adapted surveillance and surgical strategies.
Keywords: thyroid cancer, papillary thyroid carcinoma, clinical characteristic, pathological characteristic, metastases
Thyroid cancer is a malignant tumor originating from the thyroid gland and has become one of the fastest-growing cancers globally in recent years [1]. According to the 2022 cancer data reported by the National Cancer Center of China, thyroid cancer ranked as the third most common malignant tumor, with 466 100 new cases annually, accounting for 9.7% of all new cancer cases [2]. In the United States, thyroid cancer has been increasing rapidly at an annual rate of 3% [3], and it is projected to become the fourth most common cancer by 2030 [4]. The rising prevalence of thyroid cancer has become an increasingly serious clinical and public health concern. This increase in incidence may be related to advancements in medical imaging technologies, environmental factors, and improved public health awareness. However, some researchers argue that the rapid increase in thyroid cancer cases may be attributed to over-diagnosis [4].
Thyroid cancers are primarily categorized into papillary thyroid carcinoma (PTC), follicular thyroid carcinoma, medullary thyroid carcinoma, and anaplastic thyroid carcinoma based on tumor origin, degree of differentiation, and pathological features. Among these, papillary and follicular thyroid carcinomas are classified as differentiated thyroid cancers (DTC) and generally have a favorable prognosis. However, 4% to 30% of patients with DTC experience recurrence [5, 6]. Recurrence not only affects survival rates but also significantly reduces the quality of life of patients. Medullary and anaplastic thyroid cancers are relatively rare but are associated with high recurrence and metastasis rates and poor prognosis [7, 8]. Large-scale, long-term follow-up case studies are essential for evaluating the underlying causes of the significant rise in thyroid cancer incidence and for identifying potential risk factors associated with recurrence.
A comprehensive understanding of the clinical pathological characteristics and prognoses of thyroid cancer is essential for identifying risk factors and developing effective treatment plans. This study analyzed 9991 cases of thyroid cancer treated at Xijing Hospital from 2008 to 2023. A total of 9504 cases were included based on inclusion and exclusion criteria. The study aimed to examine the evolution of clinical pathological characteristics, changes in surgical approaches, and prognostic outcomes of thyroid cancer patients, providing scientific evidence to improve the diagnosis and treatment of thyroid cancer and advance clinical practice.
Materials and methods
Study population
A retrospective analysis was conducted on the clinical data of 9991 thyroid cancer patients admitted to the Department of Thyroid, Breast and Vascular Surgery, Xijing Hospital, from January 2008 to December 2023. Inclusion criteria were as follows: (1) patients undergoing surgical treatment during this hospitalization, (2) postoperative pathological diagnosis confirming thyroid cancer, and (3) complete case records. Exclusion criteria were as follows: (1) concurrent diagnoses of other malignant tumors, (2) patients undergoing radiofrequency or microwave ablation, (3) incomplete case records, and (4) patients lost to follow-up.
The study was approved by the Ethics Committee of Xijing Hospital (approval number: KY20232254-C-1).
Based on the inclusion and exclusion criteria, 9504 cases were selected for this study. Among them, there were 2527 male and 6977 female patients, with a male-to-female ratio of 1:2.76. Patient ages ranged from 6 to 87 years, with a mean age of 43.49 ± 11.53 years. The cases were divided into 3 groups based on the year of treatment: 2008 to 2013 (first 6 years), 2014 to 2018 (middle 5 years), and 2019 to 2023 (last 5 years). Patient demographics, such as gender, age, and methods of disease detection, were statistically analyzed. In this study, “health screening” refers to detection by thyroid ultrasonography during routine physical checkups, rather than by physical examination alone. Clinical pathological characteristics, such as tumor size, distribution, gene mutation results, and lymph node metastases, were also assessed. The histological subtype distribution is summarized in Table 1, with PTC accounting for 98.25% of the cohort.
Table 1.
Clinical pathological characteristics of thyroid carcinoma patients treated from 2008 to 2023
| Number of cases | Percentage (%) | |
|---|---|---|
| Pathological types | ||
| Papillary thyroid carcinoma | 9338 | 98.25 |
| Follicular thyroid carcinoma | 56 | 0.59 |
| Medullary thyroid carcinoma | 75 | 0.79 |
| Anaplastic thyroid carcinoma | 24 | 0.25 |
| Poorly differentiated thyroid carcinoma | 5 | 0.05 |
| Oncocytic thyroid carcinoma | 6 | 0.06 |
| Tumor size (cm) | ||
| ≤0.5 | 1684 | 17.72 |
| 0.5 to 1 | 3919 | 41.24 |
| 1 to 2 | 2757 | 29.01 |
| 2 to 4 | 979 | 10.30 |
| >4 | 165 | 1.74 |
| Tumor focality and distribution | ||
| Single-sided and single-focal | 5840 | 61.45 |
| Single-sided and multifocal | 1354 | 14.25 |
| Bilateral and multifocal | 2310 | 24.31 |
| Lymph node metastases | ||
| Yes | 4836 | 50.88 |
| No | 4668 | 49.12 |
| Gene mutationsa | ||
| BRAF V600E mutation | 4913 | 87.72 |
| RAS mutation | 3 | 1.06 |
| TERT mutation | 3 | 1.06 |
a A total of 5601 patients underwent BRAF V600E gene testing; 283 patients underwent RAS and TERT gene testing. The denominator for the percentage of gene testing cases is the total number of patients who underwent that specific gene test.
Papillary thyroid carcinoma patients were classified into 4 recurrence risk categories according to the 2025 American Thyroid Association (ATA) Risk Stratification System [9]. One necessary adaptation was made: because metastatic lymph node size was not systematically recorded in our pathology reports, we were unable to verify the ≤2 mm criterion required for the low-risk category. To avoid underestimation of recurrence risk, all patients with any lymph node involvement (pN1) were conservatively classified as at least low-intermediate risk.
Mutation analysis of BRAF, TERT, and NRAS in thyroid cancer
Mutational testing was performed on a voluntary basis, dependent on clinician and patient preference, rather than according to a systematic screening protocol.
Genomic DNA was isolated from formalin-fixed and paraffin-embedded (FFPE) thyroid tumor tissues. The most representative tumor areas were first selected by an experienced thyroid pathologist. Deparaffinization was performed using xylene-ethanol extraction, followed by overnight lysis with proteinase K at 56 °C. DNA was subsequently purified using the AmoyDx® FFPE DNA Kit (Amoy Diagnostics Co., Ltd., Xiamen, China) or the QIAamp DNA Mini Kit (Qiagen GmbH, Hilden, Germany) according to the manufacturers’ instructions. The extracted DNA was quantified and qualified, then stored at −40 °C until further use.
The BRAF V600E mutation was detected by polymerase chain reaction (PCR) using 100 to 300 ng of genomic DNA in a 50 μL reaction mixture containing 1× PCR buffer, 1.5 mM MgCl2, 0.2 mM dNTPs, 25 pmol of each primer, and 1 unit of Taq polymerase (Kapa Biosystems). Amplification was conducted under the following conditions: initial denaturation at 95 °C for 5 minutes; 15 cycles of 95 °C for 25 seconds, 64 °C for 20 seconds, and 72 °C for 20 seconds; followed by 31 cycles of 93 °C for 25 seconds, 60 °C for 35 seconds, and 72 °C for 20 seconds. Polymerase chain reaction products were analyzed on an ABI PRISM 3700 DNA Analyzer (Applied Biosystems). A sample was considered positive for the BRAF V600E mutation if the Ct value of the FAM signal was lower than 28.
For TERT promoter mutations (C228T and C250T), a 235-bp region encompassing these hotspots was amplified by PCR using the primers: 5′-AGTGGATTCGCGGGCACAGA-3′ (sense) and 5′-CAGCGCTGCCTGAAACTC-3′ (antisense). The PCR conditions were identical to those used for BRAF V600E detection. The amplified products were first verified by agarose gel electrophoresis, then subjected to bidirectional Sanger sequencing on an ABI 3500xl Dx Genetic Analyzer (Thermo Fisher, USA). Any detected mutation was confirmed by independent PCR and sequencing in both forward and reverse directions.
NRAS mutations in exons 2 to 4 were detected using the AmoyDx® NRAS Mutation Detection Kit (Amoy Diagnostics, Xiamen, China) on an ABI 7500 real-time PCR system (Life Technologies, Carlsbad, CA, USA). Each 40 μL reaction consisted of 5 μL DNA and 35 μL of master mix containing primers, fluorescent probes, PCR buffer, and DNA polymerase. The thermal cycling program included an initial step at 95 °C for 5 minutes, followed by 15 cycles of 95 °C for 25 seconds, 64 °C for 20 seconds, and 72 °C for 20 seconds, and then 31 cycles of 93 °C for 25 seconds, 60 °C for 35 seconds, and 72 °C for 20 seconds. Fluorescence signals from FAM and HEX channels were recorded, and NRAS mutation status was determined based on the FAM Ct value.
Follow-up of patients
The follow-up of thyroid cancer patients is divided into 3 parts. The first part involves patients who regularly revisit the outpatient department. The results of these outpatient follow-ups are entered into the Thyroid Cancer Database Management System (version 4.0), which was independently developed by the Department of Thyroid, Breast and Vascular Surgery at Xijing Hospital, by data entry personnel. The second part involves DTC patients who do not regularly revisit. They are first followed up through intelligent voice follow-up. The specific steps are as follows: first, patients who need to be followed up are screened through the Thyroid Cancer Database Management System. The basic information of the patients (hospitalization number and patient name) is then imported into the Intelligent Voice Follow-up Platform, which was independently developed by Xijing Hospital as part of its Smart Hospital initiative. A follow-up task is created and the corresponding follow-up script template—specific to DTC and covering both short-term (3-month) and long-term follow-up—is selected. The system automatically dials the patients’ phone numbers according to the plan and communicates with the patients using synthesized human-like voice, following the standard script template. The follow-up system supports multiround voice conversations and can recognize various dialects. For patients whose first follow-up attempt fails or is interrupted, the system is programmed to make a second call after a half-hour interval. If the patient still does not answer after 5 calls, it is defined as a follow-up failure. The system then categorizes such patients into a lost-to-follow-up directory. After the follow-up task is completed, the system uses voice recognition technology and audio transcoding technology to translate and analyze the collected information, automatically generating the corresponding follow-up results. All call recordings, translated text, and follow-up results were stored in a structured format. To maintain quality control, 2 case managers randomly select 10% of the intelligent follow-up call recordings and verify their accuracy by comparing the system-generated results against the original recordings. The third part involves the following patients: (1) DTC patients for whom intelligent voice follow-up failed or yielded incomplete information and (2) all patients with medullary or anaplastic thyroid cancer who did not attend regular outpatient visits. These patients were followed up by 2 case managers through manual telephone follow-up. These case managers inquired in detail about the patients’ recent ultrasound and/or pathological findings. If a patient was unable to clearly describe these results, the case managers requested that the patient provide photographs of the original reports, which were then reviewed by a physician to determine clinical status.
In the intelligent voice follow-up system, patients were asked whether they had experienced recurrence and, if so, the anatomical site. However, because the system is a voice-based platform, it only records patients’ self-reported responses and does not obtain detailed imaging findings or pathological reports. Therefore, for every patient who self-reported recurrence during intelligent voice follow-up, we conducted a verification procedure consisting of outpatient medical record review or manual telephone follow-up to confirm the recurrence status. Only verified recurrence events were included in the analysis. Among 129 patients who self-reported recurrence during intelligent voice follow-up, 24 patients (18.6%) were ultimately determined not to have true recurrence after verification. Common reasons for erroneous self-reporting of these 24 cases included (1) a contralateral lobe nodule with a TI-RADS classification of 3 or 4A but without confirmatory biopsy in patients who had undergone lobectomy and (2) benign cervical lymphadenopathy on ultrasound that did not meet criteria for structural recurrence. In both scenarios, patients had interpreted these findings as “recurrence,” whereas clinical evaluation did not support this conclusion.
Definition of recurrence
Recurrence was defined according to the following criteria. Structural recurrence was established by either pathological confirmation of malignancy on cytology or histopathology from reoperation, or by imaging evidence consisting of the appearance of new suspicious lymph nodes on neck ultrasound compared with postoperative baseline imaging, provided that these findings were deemed suspicious on at least 2 consecutive follow-up examinations. Biochemical recurrence was defined separately for DTC and medullary thyroid cancer. For DTC patients who had undergone total thyroidectomy and radioactive iodine ablation, biochemical recurrence was defined as thyroglobulin (Tg) level > 10 ng/mL with a persistent increase, or although Tg is low or even negative, the thyroglobulin autoantibody (TgAb) level is progressively elevated. For medullary thyroid cancer patients, biochemical recurrence was defined as persistently elevated or rising serum calcitonin levels above the normal reference range; carcinoembryonic antigen levels were not routinely measured in this cohort and were therefore not included in the definition. A patient was classified as having recurrence in this study only if they met the criteria for structural recurrence, either alone or in combination with biochemical recurrence; isolated biochemical recurrence without corresponding structural evidence was not considered a recurrence event.
Statistical analysis
Statistical analysis was performed using SPSS 26.0 software. Continuous variables were expressed as mean ± SD (x̅ ± SD), and group comparisons were conducted using independent t-tests. Categorical variables were expressed as frequencies, and group comparisons were analyzed using chi-square or Fisher's exact tests. Univariate and multivariate binary logistic regression analyses were performed to identify risk factors associated with recurrence, with results expressed as odds ratios and 95% CIs. Recurrence-free survival (RFS) was estimated using the Kaplan–Meier method, and differences between groups were compared using the log-rank test. A P value of <.05 was considered statistically significant.
Results
Demographic characteristics of newly diagnosed thyroid cancer patients
A total of 9504 thyroid cancer cases met the inclusion and exclusion criteria in this study, among which 9317 were new cases, accounting for 98.03%. As shown in Fig. 1A, except for the years 2018 to 2020, which were affected by hospital reforms and the COVID-19 pandemic, the number of new thyroid cancer cases has shown an increasing trend from 2008 to 2023. In terms of patient gender, the male-to-female ratio among all new cases was 1:2.76. As shown in Fig. 1B, the proportion of male patients fluctuated over time but showed an overall increasing trend, rising from 14.29% in 2008 to 33.61% in 2023. The gender-stratified annual case numbers (Fig. S1A [10]) further illustrate that female cases increased rapidly from 2008 to 2014, then plateaued between 2015 and 2020, and remained relatively stable through 2021 to 2023. Male cases showed a steady rise from 2008 to 2014, fluctuated between 2015 and 2020, and resumed growth after 2020. Regarding patient age, as shown in Fig. 1C, during the period from 2008 to 2023, the age group of 30 to 60 years has consistently been the highest-incidence age group for thyroid cancer, with a proportion ranging from 65.31% to 81.71%. The proportion of patients under 18 years of age has shown a year-on-year downward trend. The proportion of patients over 60 years of age decreased year-by-year from 2008 to 2016, and then fluctuated upward after 2017. In terms of the detection methods for thyroid cancer, as shown in Fig. 1D, the proportion of patients detected through physical examinations (thyroid ultrasonography) has increased year-by-year, rising from 18.37% in 2008 to 91.13% in 2023. In contrast, the proportion of patients detected through self-detected mass has decreased year-by-year, falling from 67.35% in 2008 to 4.39% in 2023. The proportions of patients who were incidentally detected through other diseases or detected due to hoarseness/neck discomfort have always been low, and since 2016, the proportions of these 2 detection methods have both remained below 5%. When stratified by gender (Fig. S1B [10]), the proportion of physical examination-detected cases within each sex increased substantially over time. The male rate was higher than the female rate for most of the study period (eg, 93.2% vs 90.1% in 2023), with a larger gap in the early years that gradually narrowed.
Figure 1.
Popularity characteristics of patients with thyroid cancer admitted from 2008 to 2023. (A) Statistics on the number of new cases every year; (B) gender changes of new cases; (C) age changes of new cases; (D) changes in the detection methods of new cases.
Surgical trends in newly diagnosed thyroid cancer patients
The newly diagnosed thyroid cancer patients included in this study were categorized into 3 groups based on the year of diagnosis: the first 6 years (2008-2013), the middle 5 years (2014-2018), and the most recent 5 years (2019-2023). Comparisons among these groups revealed a trend toward reduced surgical extent in thyroid cancer operations. As shown in Fig. 2A, the proportion of patients undergoing total thyroidectomy gradually decreased, with respective proportions of 87.82%, 76.00%, and 57.17% in the first 6 years, the middle 5 years, and the most recent 5 years. Conversely, the proportion of patients undergoing unilateral thyroid lobectomy gradually increased, with proportions of 12.18%, 24.00%, and 42.53% in the respective time periods. Chi-square test revealed a significant overall difference across the 3 time periods (χ2 = 553.970; P < .001). Significant changes were also observed in the approaches to lymph node dissection. As shown in Fig. 2B, the proportion of patients undergoing “ipsilateral central neck dissection” significantly increased, with respective proportions of 11.82%, 19.70%, and 39.52% in the first 5 years, the middle 5 years, and the most recent 5 years. In contrast, the proportions of “bilateral central neck dissection” and “bilateral central neck plus bilateral lateral neck dissection” both decreased markedly. The overall difference across the 3 time periods was statistically significant (χ2 = 1067.978; P < .001).
Figure 2.
Comparison of surgical methods for new thyroid cancer patients admitted from 2008 to 2023, grouped by year. (A) Thyroid lobe resection method; (B) thyroid lymph node dissection method. Data were compared using the chi-square test. Overall differences across the 3 time periods were significant for both surgical extent (χ2 = 553.970; P < .001) and lymph node dissection approach (χ2 = 1067.978; P < .001).
Clinical pathological characteristics
As shown in Table 1, the clinical pathological features of 9504 cases (including 9317 newly diagnosed and 187 recurrent cases) were analyzed. Pathological types: PTC accounted for 98.25%, followed by follicular thyroid carcinoma (0.59%), medullary thyroid carcinoma (0.79%), and anaplastic thyroid carcinoma (0.25%). Tumor size: tumors ≤1 cm accounted for 58.96% of cases, tumor size between 1 and 2 cm accounted for 29.01% of cases, tumor size between 2 and 4 cm accounted for 10.30% of cases, while tumors >4 cm represented only 1.74%. Tumor focality and distribution: single-sided and single-focal tumors accounted for 61.45% of cases. Lymph node metastases: 4836 patients (50.88%) exhibited lymph node metastasis. Gene mutations: BRAF V600E was tested in 5601 patients (87.72% positive). RAS and TERT mutations were tested in only 283 patients, with only 3 positive cases (1.06%).
Comparison of clinical pathological characteristics over time between 2008 and 2023
The included patients with thyroid cancer were divided into 3 groups according to the year of diagnosis: the first 6 years (2008-2013), the middle 5 years (2014-2018), and the most recent 5 years (2019-2023). The clinical and pathological characteristics of the patients were compared among these groups. As shown in Fig. 3A, during the period from 2008 to 2023, the proportion of patients with primary tumor sizes of ≤0.5 cm and 0.5 to 1 cm gradually increased, while the proportion of patients with tumor sizes of 2 to 4 cm and >4 cm gradually decreased. Chi-square test revealed a significant overall difference across the 3 time periods (χ2 = 776.954; P < .001). Regarding the number and location of the lesions, as shown in Fig. 3B, the proportion of patients with unilateral single lesions gradually decreased, while the proportion of patients with unilateral multifocal lesions and bilateral multifocal lesions gradually increased. The overall difference across the 3 time periods was statistically significant (χ2 = 66.256; P < .001). For patients with thyroid cancer who underwent genetic testing, the mutation rate of BRAF V600E gradually increased, reaching 90.78% during 2019 to 2023 (Fig. 3C). Chi-square test showed a significant overall difference across the 3 time periods (χ2 = 69.757; P < .001). In terms of lymph node metastasis, the proportion of patients found to have lymph node metastasis gradually increased (Fig. 3D), from 43.39% during 2008 to 2013 to 53.99% during 2019 to 2023. The overall difference across the 3 time periods was statistically significant (χ2 = 48.261; P < .001). Further analysis of the location of lymph node metastasis revealed (Fig. 3E) that the proportion of patients with central lymph node metastasis gradually increased, from 36.05% during 2008 to 2013 to 48.77% during 2019 to 2023; in contrast, the proportion of patients with lateral lymph node metastasis remained relatively stable at around 20%. Chi-square test revealed a significant overall difference across the 3 time periods for central neck metastasis (χ2 = 13.326; P = .001). Analysis of the number of lymph node metastases showed (Fig. 3F) that the proportion of patients with ≤5 metastatic lymph nodes gradually increased, from 29.13% during 2008 to 2013 to 39.77% during 2019 to 2023, whereas the proportion of patients with >5 metastatic lymph nodes remained relatively stable at around 14%. The overall difference across the 3 time periods was statistically significant (χ2 = 9.150; P = .01). To further investigate the factors contributing to the increasing lymph node metastasis rate, we stratified patients by preoperative clinical nodal status (cN0 vs cN+). Among cN0 patients, the prophylactic central neck dissection (pCLND) rate (ie, cN0 patients who underwent central lymph node dissection) was 90.16% in 2008 to 2013, 88.68% in 2014 to 2018, and 95.18% in 2019 to 2023, with a significant overall difference across the 3 periods (χ2 = 81.502; P < .001). The occult metastasis rate (pathologically positive nodes among cN0 patients who underwent lymph node dissection) increased significantly from 30.05% in 2008 to 2013 to 37.31% in 2014 to 2018 and further to 42.09% in 2019 to 2023 (χ2 = 39.751; P < .001).
Figure 3.
The clinical pathological characteristics of patients with thyroid cancer from 2008 to 2023 are compared by annual groups. (A) The size of the lesion; (B) the number of lesions and distribution; (C) the BRAF V600E gene mutation; (D) lymph node metastasis; (E) the position distribution of the lymph nodes; (F) distribution of the number of metastatic lymph nodes. Data were compared using the chi-square test. Overall differences across the 3 time periods were significant for all variables shown: tumor size (χ2 = 776.954; P < .001), tumor focality and distribution (χ2 = 66.256; P < .001), BRAF V600E mutation (χ2 = 69.757; P < .001), lymph node metastasis (χ2 = 48.261; P < .001), location of lymph node metastases (χ2 = 13.326; P = .001), and number of metastatic lymph nodes (χ2 = 9.150; P = .01).
Prognostic analysis of thyroid cancer
A long-term follow-up was conducted on 9504 cases of thyroid cancer, with a follow-up duration ranging from 8 to 300 months and a median follow-up time of 69 months. During the follow-up period, a total of 374 patients experienced recurrence, with a recurrence rate of 3.94%. Given that PTC accounted for 98.25% of the cohort, we performed a subgroup analysis restricted to PTC patients (n = 9338). As shown in Table 2, a comparison of case characteristics between the recurrence group and the nonrecurrence group revealed statistically significant differences in age, tumor size, presence of lymph node metastasis, the number of metastatic lymph nodes, and ATA risk stratification. Specifically, the proportion of patients aged >55 years old was higher in the recurrence group (recurrence vs nonrecurrence: 20.6% vs 15.0%, P < .001). The proportion of patients with tumor sizes ≤1 cm was lower in the recurrence group (recurrence vs nonrecurrence: 31.5% vs 60.5%, P < .001), while the proportions of patients with tumor sizes of 2 to 4 cm (recurrence vs nonrecurrence: 26.8% vs 9.3%, P < .001) and >4 cm (recurrence vs nonrecurrence: 5.9% vs 1.5%, P < .001) were higher. The proportion of patients with lymph node metastasis detected during the initial surgery was higher in the recurrence group (recurrence vs nonrecurrence: 77.9% vs 50.1%, P < .001). Additionally, the proportion of patients with >5 metastatic lymph nodes was higher in the recurrence group (recurrence vs nonrecurrence: 49.6% vs 26.2%, P < .001). The recurrence rates stratified by the 2025 ATA initial risk categories were 0.9% for low risk, 4.4% for low–intermediate risk, and 7.1% for intermediate–high risk (χ2 = 131.304; P < .001). No patients met the criteria for the high-risk category.
Table 2.
Univariate analysis of long-term follow-up results of patients with papillary thyroid cancer admitted from 2008 to 2023
| Recurrence group, n = 321 | Nonrecurrence group, n = 9017 | χ2 | P value | |
|---|---|---|---|---|
| Gender | 0.859 | .367 | ||
| Male | 92 (28.7%) | 2375 (26.3%) | ||
| Female | 229 (71.3%) | 6642 (73.7%) | ||
| Age | 9.829 | .007 | ||
| ≤35 | 94 (29.3%) | 2463 (27.3%) | ||
| 35 to 55 | 161 (50.2%) | 5202 (57.7%) | ||
| >55 | 66 (20.6%) | 1352 (15.0%) | ||
| Tumor size | 181.235 | <.001 | ||
| ≤1 cm | 101 (31.5%) | 5452 (60.5%) | ||
| 1 to 2 cm | 115 (35.8%) | 2589 (28.7%) | ||
| 2 to 4 cm | 86 (26.8%) | 841 (9.3%) | ||
| >4 cm | 19 (5.9%) | 135 (1.5%) | ||
| The presence of lymph node metastasis | 95.928 | <.001 | ||
| Yes | 250 (77.9%) | 4515 (50.1%) | ||
| No | 71 (22.1%) | 4502 (49.9%) | ||
| The number of metastasis lymph nodes | 65.153 | <.001 | ||
| ≤5 | 126 (50.4%) | 3332 (73.8%) | ||
| >5 | 124 (49.6%) | 1183 (26.2%) | ||
| ATA risk stratification | 131.304 | <.001 | ||
| Low | 32 (0.9%) | 3488 (99.1%) | ||
| Low–intermediate | 196 (4.4%) | 4305 (95.6%) | ||
| Intermediate–high | 93 (7.1%) | 1224 (92.9%) |
Bold values indicate statistical significance (P < .05).
Further analysis was conducted using binary logistic regression to identify independent risk factors for thyroid cancer recurrence. As shown in Table 3, age, tumor size, the number of metastatic lymph nodes, and ATA risk stratification were identified as independent risk factors for thyroid cancer recurrence. Patients with thyroid cancer aged >55 years old had a 1.966-fold increased risk of recurrence compared with those aged ≤35 years old (OR = 1.966; 95% CI = 1.396-2.770; P < .001). Patients with tumor sizes of 1 to 2 cm had a 1.942-fold increased risk of recurrence compared with those with tumor sizes ≤1 cm (OR = 1.942; 95% CI = 1.440-2.619; P < .001). Patients with tumor sizes of 2 to 4 cm had a 3.842-fold increased risk of recurrence compared with those with tumor sizes ≤1 cm (OR = 3.842; 95% CI = 2.751-5.368; P < .001), and patients with tumor sizes >4 cm had a 6.243-fold increased risk of recurrence compared with those with tumor sizes ≤1 cm (OR = 6.243; 95% CI = 3.594-10.842; P < .001). Patients with 1 to 5 metastatic lymph nodes had a 2.024-fold increased risk of recurrence compared with those without lymph node metastasis (OR = 2.024; 95% CI = 1.495-2.741; P < .001), and patients with >5 metastatic lymph nodes had a 3.341-fold increased risk of recurrence compared with those without lymph node metastasis (OR = 3.341; 95% CI = 2.381-4.689; P < .001). Patients with low–intermediate ATA risk stratification had a 4.001-fold increased risk of recurrence compared with those with low-risk stratification (OR = 4.001; 95% CI = 2.705-5.918; P < .001), and patients with intermediate–high ATA risk stratification had a 3.105-fold increased risk of recurrence compared with those low-risk stratification (OR = 3.105; 95% CI = 2.001-4.818; P < .001). For comparison, we also analyzed the full cohort (Tables S1 and S2 [10]), which yielded essentially identical results, reflecting that the findings are primarily driven by the PTC subgroup.
Table 3.
Multivariate logistic regression analysis of long-term follow-up results of patients with papillary thyroid cancer admitted from 2008 to 2023
| P value | OR | 95% CI | |
|---|---|---|---|
| Age | |||
| ≤35 | <.001 | ||
| 35 to 55 | .119 | 1.244 | 0.946 to 1.636 |
| >55 | <.001 | 1.966 | 1.396 to 2.770 |
| Tumor size | |||
| ≤1 cm | <.001 | ||
| 1 to 2 cm | <.001 | 1.942 | 1.440 to 2.619 |
| 2 to 4 cm | <.001 | 3.842 | 2.751 to 5.368 |
| >4 cm | <.001 | 6.243 | 3.594 to 10.842 |
| The number of lymph node metastases | |||
| 0 | <.001 | ||
| 1 to 5 | <.001 | 2.024 | 1.495 to 2.741 |
| >5 | <.001 | 3.341 | 2.381 to 4.689 |
| ATA risk stratification | |||
| Low | <.001 | ||
| Low–intermediate | <.001 | 4.001 | 2.705 to 5.918 |
| Intermediate–high | <.001 | 3.105 | 2.001 to 4.818 |
Among medullary thyroid carcinoma patients with available Ki-67 data (n = 44), the rates of lymph node metastasis (64.0% vs 42.1%) and recurrence (40.0% vs 15.8%) were higher in the Ki-67 ≥ 5% group, and the differences did not reach statistical significance (P = .223 and P = .105, respectively) (Table S326).
The RFS curves, as shown in Fig. 4, revealed that the 200-month RFS rate was 82.7% (95% CI = 73.7-91.7%) for patients with PTC, 79.1% (95% CI = 67.3-90.9%) for patients with follicular thyroid cancer, 58.6% (95% CI = 41.2-76.0%) for patients with medullary thyroid cancer, and 5.6% (95% CI = 0-16.0%) for patients with anaplastic thyroid cancer. To further evaluate temporal trends in recurrence, we performed Kaplan–Meier analyses stratified by time period within the PTC subgroup (Fig. S226). The RFS proportions were 89.8% (2008-2013), 97.3% (2014-2018), and 97.8% (2019-2023) (log rank χ2 = 40.948; P < .001), but this comparison is confounded by unequal observation windows (mean follow-up: 185.7, 128.4, and 69.6 months). To ensure comparability, we restricted the analysis to recurrences within 5 years, censoring at 60 months (Fig. S326). The 5-year RFS proportions were 94.9%, 97.9%, and 97.8%, respectively (log rank χ2 = 26.013; P < .001). The lower rate in the earliest period and the near-identical rates in the 2 later periods suggest that contemporary treatment protocols (2014-2023) have achieved favorable short- to intermediate-term outcomes, while the higher crude rate in 2008 to 2013 reflects both elevated early recurrence and prolonged surveillance.
Figure 4.
Recurrence-free survival curve of thyroid cancer patients.
Discussion
Global epidemiological studies show a significant increase in the incidence of thyroid cancer, particularly in PTC [11]. From 2008 to 2023, the number of new thyroid cancer cases treated at our hospital demonstrated a consistent upward trend, with 98.25% of cases being PTC. Increased public health awareness has contributed to this rise, as the proportion of cases detected through health checkups grew from 18.37% in 2008 to 91.13% in 2023. In our study, the overall male-to-female ratio for new cases was 1:2.76, and the proportion of male patients increased over time. Our gender-stratified analysis indicates that the rising proportion of male patients is not due to lower screening coverage in males; rather, it reflects a plateau in female cases and a recent resurgence in male cases. These findings highlight the need for further investigation into sex-specific drivers of thyroid cancer detection and incidence. Retrospective analyses of the SEER database from 2004 to 2018 also reported a rising proportion of male thyroid cancer patients, with a male-to-female ratio of 1:3.13 [12]. In our study, patients aged 30 to 60 years consistently accounted for the majority of cases, which aligns with findings from the DisMod-MR database (1991-2021), showing that the peak age range for thyroid cancer incidence globally is 30 to 79 years [13]. Nevertheless, the proportion of thyroid cancer patients over 60 years old was relatively low in our cohort.
In addition, we observed notable changes in clinical pathological characteristics from 2008 to 2023, including a rise in the proportion of tumors ≤1 cm and an increase in multifocal cases. Over the past few decades, the incidence of thyroid microcarcinoma has grown exponentially, which can be attributed to advancements in ultrasound diagnostics and fine-needle aspiration [14, 15]. However, few studies have specifically examined the changing detection rates of tumors ≤0.5 cm and 0.5 to 1 cm. Our study found that the proportion of tumors 0.5 to 1 cm increased at a faster rate. Research suggests that tumors in the 0.5 to 1 cm range are more likely to exhibit extrathyroidal invasion compared with smaller lesions (<0.5 cm) [16]. This finding underscores the clinical importance of vigilant assessment for tumors in the 0.5 to 1 cm range, as their increasing incidence and greater invasive potential may warrant closer surveillance than lesions below 0.5 cm. The observed increase in the proportion of unilateral multifocal and bilateral multifocal lesions over time is noteworthy. This trend may be largely attributable to increasingly meticulous pathological evaluation. Park et al [17] performed whole-specimen mapping with 2 mm serial sectioning in 82 patients with a preoperative diagnosis of solitary PTC and found that 45.1% harbored occult PTC foci missed by ultrasound; 92.5% of these occult lesions were <3 mm, and 30.5% of patients had contralateral lobe involvement. As institutional pathology protocols gradually adopted more systematic sampling, these previously undetected microfoci were increasingly captured and classified, thereby raising the reported rates of multifocality and bilaterality. Notably, the proportion of total thyroidectomy declined substantially during the same period, arguing against the possibility that more extensive surgical resection drove the increased detection of additional lesions. Furthermore, improvements in ultrasound technology and the widespread use of screening ultrasonography have facilitated the preoperative identification of small additional nodules, contributing to the observed trend. However, we cannot exclude the possibility that a true increase in multifocal disease also contributed to this trend, and the relative contributions of detection bias vs biological change remain uncertain.
Additionally, we found that lymph node metastases became more common, increasing from 43.39% in 2008 to 2013 to 53.99% in 2019 to 2023. This rise was primarily due to central lymph node involvement and metastases in ≤5 nodes. Lymph node metastasis is significant prognostic factor for thyroid cancer [18]. Patients with lymph node metastases, especially those with lateral cervical node involvement or a higher number of affected nodes, tend to have poorer prognoses [19]. To explore the underlying causes of the increasing lymph node metastasis rate, we stratified patients by preoperative clinical nodal status. Among cN0 patients, the pCLND rate first slightly decreased (90.2-88.7%) then increased to 95.2% throughout the study period, while the occult metastasis rate (cN0/pN+) rose steadily from 30.1% to 42.1%. This pattern indicates that the increasing metastasis rate was not driven by expanded prophylactic dissection nor by improved preoperative ultrasound (which would have decreased occult metastases). Instead, the concurrent rise in BRAF V600E mutation rate (from ∼70% to 90.8%) and the steady increase in occult metastases point to biological changes (increased metastatic potential) and improved pathological detection of micrometastases (eg, serial sectioning and immunohistochemistry). Recent advances in the preoperative and intraoperative assessment of cervical lymph nodes, including improved characterization of small or indeterminate nodes, have enhanced the detection of lymph node metastases compared with conventional methods [20]. These findings indicate that with increased public health awareness and advances in detection technology, we can not only identify low-risk patients earlier but also recognize high-risk patients with multiple lesions and lymph node metastasis. The rising central metastasis rate also highlights the need for detailed risk assessments and more precise treatment strategies.
It is important to acknowledge the divergent guideline recommendations regarding pCLND between China and Western countries. The 2025 ATA guidelines provide a strong recommendation against pCLND for most small, noninvasive, clinically node-negative papillary thyroid cancers (cT1-T2, cN0) and for most follicular thyroid cancers [9]. In contrast, the Chinese national guidelines have consistently recommended at least ipsilateral central compartment dissection for DTC when parathyroid glands and recurrent laryngeal nerves can be effectively preserved [21]. Our institutional practice reflects this latter approach. The high prophylactic dissection rates observed throughout the study period (88.7-95.2%) are therefore a direct consequence of adherence to Chinese guidelines. The decision to perform pCLND must carefully balance the staging and prognostic benefits against the risk of surgical complications, particularly hypoparathyroidism and recurrent laryngeal nerve injury.
Our study also identified age, tumor size, and the number of lymph node metastases as independent risk factors for recurrence in PTC. This is consistent with previous research. For instance, a recurrence risk model for PTC based on 955 cases identified age >55 years as a risk factor [22]. Other studies have similarly reported that age >45 or >55 years is a key factor in recurrence risk stratification in the ATA guidelines [23]. Tumor size was also a critical risk factor. Our study showed that the recurrence risk increased significantly with tumor size in PTC: patients with tumors 1 to 2 cm, 2 to 4 cm, and >4 cm had recurrence risks 1.942, 3.842, and 6.243 times higher, respectively, compared with those with tumors ≤1 cm. These findings align with meta-analyses and large-scale retrospective studies, which consistently report that larger tumor sizes are associated with higher recurrence risks [19, 24]. Lymph node metastases are widely recognized as a major predictor of recurrence [24]. A retrospective study including 1209 patients with T1 PTC indicated that lymph node metastasis positivity is an independent risk factor for patient recurrence [25]. Another study retrospectively analyzed 310 patients with cN1a PTC and found that involvement of ≥3 central lymph nodes is an independent predictor of lateral neck lymph node recurrence [26]. In our study, patients with 1 to 5 affected nodes had a recurrence risk 2.024 times higher than those without metastases, while patients with >5 affected nodes had a risk 3.341 times higher. The identified risk factors for PTC recurrence in this study enable medical professionals to better stratify patients according to their recurrence risk, thereby facilitating more personalized and targeted treatment strategies.
Our study has several limitations: (1) The data were derived from a single medical center, which may limit the generalizability of our findings. The specific characteristics and treatment protocols of our center may influence the results. Future multicenter studies are needed to validate our conclusions across broader populations. (2) Complete iodine-131 data were unavailable in our study. Including iodine-131 data in future studies could provide a more comprehensive understanding of factors influencing recurrence. (3) Molecular testing was patient driven and incomplete (BRAF: 60% of PTC; RAS/TERT: very small subset), and no genetic testing was performed for medullary thyroid carcinoma cases. BRAF V600E was not included in the multivariable model due to missing data and selection bias. Future prospective studies with standardized molecular testing are needed to validate the prognostic role of these mutations. (4) Systematic data on tumor necrosis, mitotic activity, and metastatic deposit size were unavailable. Ki-67 was available in only 44/75 MTC cases, precluding definitive analysis. (5) American Thyroid Association risk stratification was limited by the absence of metastatic lymph node size data, necessitating conservative assignment of all pN1 patients to at least the low–intermediate category. Dynamic risk stratification could not be performed because early postoperative thyroglobulin and ultrasound data were incompletely captured in our follow-up database. Despite these limitations, our study offers valuable insights into the risk factors for thyroid cancer recurrence and serves as a foundation for future research.
This study analyzed 9504 cases of thyroid cancer treated at Xijing Hospital from 2008 to 2023, with a median follow-up of 69 months. The clinical pathological characteristics, surgical trends, and prognostic factors of thyroid cancer patients were evaluated: (1) The number of new cases has increased, with most patients diagnosed through health checkups. (2) Male patients account for a growing proportion of cases, while the percentage of juvenile patients has declined. (3) Surgical approaches have shifted toward more conservative methods, with smaller resection areas. (4) Most cases were PTC, with approximately half of the patients exhibiting lymph node metastases. (5) Tumor sizes have decreased over time, while multifocal lesions, BRAF V600E mutations, and lymph node metastases have become more common. (6) Age >55 years, larger tumor size, and a higher number of lymph node metastases were identified as independent risk factors for recurrence in PTC. These findings provide critical insights into improving thyroid cancer diagnosis, treatment, and follow-up strategies.
Contributor Information
Sijin Guo, Department of Thyroid, Breast and Vascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi’an, Shaanxi 710032, China.
Yang Wang, Department of Thyroid, Breast and Vascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi’an, Shaanxi 710032, China.
Changjiao Yan, Email: yanchangjiao@fmmu.edu.cn, Department of Thyroid, Breast and Vascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi’an, Shaanxi 710032, China.
Ting Wang, Email: wangting@fmmu.edu.cn, Department of Thyroid, Breast and Vascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi’an, Shaanxi 710032, China.
Author contributions
All authors have made substantial contributions to this work. S.G. and T.W. were responsible for the study conception and design. Y.W. collected and managed the patient data. C.Y. performed the statistical analysis and data interpretation. The initial manuscript draft was prepared by C.Y., and all authors critically reviewed, revised, and approved the final version of the manuscript for submission.
Disclosures
The authors report no conflicts of interest in this work.
Data availability
The authors confirm that the data supporting the findings of this study are available within the article. Any additional data not included can be requested from the corresponding author, upon reasonable request.
Ethics approval
The study was approved by the Ethics Committee of Xijing Hospital, Fourth Military Medical University (approval number: KY20232254-C-1).
References
- 1. Boucai L, Zafereo M, Cabanillas ME. Thyroid cancer: a review. JAMA. 2024;331(5):425‐435. [DOI] [PubMed] [Google Scholar]
- 2. Han B, Zheng R, Zeng H, et al. Cancer incidence and mortality in China, 2022. J Natl Cancer Cent. 2024;4(1):47‐53. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Lim H, Devesa SS, Sosa JA, Check D, Kitahara CM. Trends in thyroid cancer incidence and mortality in the United States, 1974-2013. JAMA. 2017;317(13):1338‐1348. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Rahib L, Smith BD, Aizenberg R, Rosenzweig AB, Fleshman JM, Matrisian LM. Projecting cancer incidence and deaths to 2030: the unexpected burden of thyroid, liver, and pancreas cancers in the United States. Cancer Res. 2014;74(11):2913‐2921. [DOI] [PubMed] [Google Scholar]
- 5. Ywata de Carvalho A, Kohler HF, Gomes CC, Vartanian JG, Kowalski LP. Predictive factors for recurrence of papillary thyroid carcinoma: analysis of 4,085 patients. Acta Otorhinolaryngol Ital. 2021;41(3):236‐242. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6. Chan S, Karamali K, Kolodziejczyk A, et al. Systematic review of recurrence rate after hemithyroidectomy for low-risk well-differentiated thyroid cancer. Eur Thyroid J. 2020;9(2):73‐84. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. Cosway B, Fussey J, Kim D, Wykes J, Elliott M, Smith J. Sporadic medullary thyroid cancer: a systematic review and meta-analysis of clinico-pathological and mutational characteristics predicting recurrence. Thyroid Res. Jul 22 2022;15(1):12. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Lee H, Kim SY, Kim SM, et al. Long-term survival of patients with anaplastic thyroid cancer after multimodal treatment. Transl Cancer Res. Sep 2020;9(9):5430‐5436. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Ringel MD, Sosa JA, Baloch Z, et al. American thyroid association management guidelines for adult patients with differentiated thyroid cancer. Thyroid. Aug 2025;35(8):841‐985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Guo S, Wang Y, Yan C, et al. Clinical and Pathological Profile with Prognostic Insights in 9504 Thyroid Cancer Cases: A Single-Center Study (2008-2023). Figshare, 2026. Deposited. 10.6084/m9.figshare.32274615. [DOI]
- 11. Bray F, Laversanne M, Sung H, et al. Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2024;74(3):229‐263. [DOI] [PubMed] [Google Scholar]
- 12. Li P, Ding Y, Liu M, Wang W, Li X. Sex disparities in thyroid cancer: a SEER population study. Gland Surg. 2021;10(12):3200‐3210. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Huang K, Huang X, Qian S, Cai Y, Wu F, Luo D. Temporal trends of thyroid cancer in China and globally from 1990 to 2021: an analysis of the global burden of disease study 2021. Sci Rep. Oct 26 2024;14(1):25538. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Xu S, Han Y. The overdiagnosis of thyroid micropapillary carcinoma: the rising incidence, inert biological behavior, and countermeasures. J Oncol. 2021;2021:5544232. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15. Gao R, Jia X, Liang Y, et al. Papillary thyroid micro carcinoma: the incidence of high-risk features and its prognostic implications. Front Endocrinol (Lausanne). 2019;10:74. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16. Bradley NL, Wiseman SM. Papillary thyroid microcarcinoma: the significance of high risk features. BMC Cancer. 2017;17(1):142. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17. Park SY, Jung YS, Ryu CH, et al. Identification of occult tumors by whole-specimen mapping in solitary papillary thyroid carcinoma. Endocr Relat Cancer. Aug 2015;22(4):679‐686. [DOI] [PubMed] [Google Scholar]
- 18. Wang LY, Ganly I. Nodal metastases in thyroid cancer: prognostic implications and management. Future Oncol (London, England). 2016;12(7):981‐994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19. Guo K, Wang Z. Risk factors influencing the recurrence of papillary thyroid carcinoma: a systematic review and meta-analysis. Int J Clin Exp Pathol. 2014;7(9):5393‐5403. [PMC free article] [PubMed] [Google Scholar]
- 20. Hu A, Tian J, Deng X, et al. The diagnosis and management of small and indeterminate lymph nodes in papillary thyroid cancer: preoperatively and intraoperatively. Front Endocrinol (Lausanne). 2024;15:1484838. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21. CSo E, TaMSGotCSo S, Association CA-C, CAoHaN O, CSoN M. Guidelines for the diagnosis and management of thyroid nodules and differentiated thyroid cancer (second edition). Chin J Endocrinol Metab. 2023;39(3):181‐226. [Google Scholar]
- 22. Li Y, Tian J, Jiang K, et al. Risk factors and predictive model for recurrence in papillary thyroid carcinoma: a single-center retrospective cohort study based on 955 cases. Front Endocrinol (Lausanne). 2023;14:1268282. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23. Zuhur SS, Aggul H, Çelik M, et al. Can age at diagnosis and sex improve the performance of the American thyroid association risk stratification system for prediction of structural persistent and recurrent disease in patients with differentiated thyroid carcinoma? A multicenter study. Endocr Pract. Jan 2022;28(1):30‐35. [DOI] [PubMed] [Google Scholar]
- 24. Valizadeh P, Jannatdoust P, Ghadimi DJ, et al. Predicting lymph node metastasis in thyroid cancer: systematic review and meta-analysis on the CT/MRI-based radiomics and deep learning models. Clin Imaging. 2025:119: 110392. [DOI] [PubMed] [Google Scholar]
- 25. Qin C, Cai S, Yin M, et al. Association of lymph nodes positive rate with the risk of recurrence in patients with stage T1 papillary thyroid cancer. J Endocr Soc. Jul 1 2024;8(8):bvae131. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26. Long B, Luo M, Zhou K, Zheng T, Li W. Risk factors and distribution pattern of lateral lymph node recurrence after central neck dissection for cN1a papillary thyroid carcinoma. BMC Surg. Sep 27 2024;24(1):270. [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.
Data Citations
- Guo S, Wang Y, Yan C, et al. Clinical and Pathological Profile with Prognostic Insights in 9504 Thyroid Cancer Cases: A Single-Center Study (2008-2023). Figshare, 2026. Deposited. 10.6084/m9.figshare.32274615. [DOI]
Data Availability Statement
The authors confirm that the data supporting the findings of this study are available within the article. Any additional data not included can be requested from the corresponding author, upon reasonable request.