Textbook Outcome After Oral Cancer Surgery as a Composite Measure for Survival and Quality‐of‐Care Evaluation

Abstract

Objective

To enhance survival outcomes for oral cavity cancer (OCC) surgery, a composite measure has been developed: “textbook outcome” (TO). Three studies have reported on this concept in OCC, but the need for population‐level results remains. This study investigates OCC surgery, focusing on survival and hospital‐level results.

Study Design

Cohort study.

Setting

National multicenter study.

Methods

All first primary OCC patients who underwent curative tumor resection between 2018 and 2021 were selected from the Dutch Head and Neck Audit database. Resections were categorized as local or extensive, the latter including neck dissection and/or free or pedicled flap reconstruction. TO was defined as the absence of 30‐day mortality, hospital readmission, prolonged length‐of‐stay, severe complications, surgical margins <1 mm, and <18 lymph nodes per side. Adjusted hazard ratios (aHRs) were determined for 2‐year overall survival (OS) and disease‐free survival (DFS).

Results

TO was reached in 81.1% and 46.9% after local (1039 patients) and extensive (1227 patients) resection, respectively. Reduced TO rates were observed in females, non‐squamous cell carcinoma, cT3‐T4, and floor of mouth compared to tongue. Obtaining TO was significantly associated with less adjuvant therapy and improved 2‐year survival after local (aHR 0.55 OS P = .004, 0.70 DFS P = .085) and extensive (aHR 0.61 OS P ≤ .001, 0.69 DFS P = .002) surgery. After correction for population differences, no interhospital variation in TO remained.

Conclusion

Achieving TO is strongly linked to improved survival, highlighting its importance as a short‐term composite quality‐of‐care indicator. The separate outcomes that were influential to the hospital's TO score differed between hospitals, indicating opportunities to improve outcomes.

Oral cavity cancer (OCC) presents as progressive tumors in a functionally critical area, necessitating complex, integrated care. ¹ Researchers continue to identify the best parameters to predict and improve survival outcomes for OCC patients. Examples of surgical outcome indicators include unplanned reoperations, complication rates, margin status, and 30‐day mortality. ¹ , ² , ³ However, these indicators often focus on a single aspect, despite the multidimensional nature of OCC care. The concept of “textbook outcome” has been developed to provide a more holistic assessment. This is a composite outcome measure used in several surgical fields. ⁴ , ⁵ , ⁶ , ⁷ , ⁸ , ⁹ By combining indicators of surgical quality and perioperative evaluation, the textbook outcome provides a comprehensive evaluation of surgical outcomes.

Associations between textbook outcome and long‐term survival have been described in two oral cancer studies and several surgical oncologic fields. ¹⁰ , ¹¹ , ¹² , ¹³ Nevertheless, there remains a need for textbook outcome analysis on larger cohorts. Moreover, as the textbook outcome covers short‐term surgical outcomes, it can guide quality care and hospital performance evaluation. ¹⁴ Clinical auditing has been introduced in recent decades to enhance the quality of care for OCC patients. ¹ , ¹⁵ Since 2014, the quality of head and neck cancer (HNC) has been monitored and benchmarked with quality indicators in the Dutch Head and Neck Audit (DHNA). ² These indicators evaluate structural, procedural, and outcome‐based measures to compare hospital performance on a national scale. ¹⁶ Before the textbook outcome can be incorporated as a quality indicator, the existence of hospital variation and the impact of patient and tumor characteristics have to be investigated. ¹⁷

This study aimed to investigate rates of textbook outcome after OCC surgery in the Netherlands and the association with overall survival (OS) and disease‐free survival (DFS). Moreover, the use of textbook outcome as a metric for quality‐of‐care evaluation is assessed. ¹⁴ , ¹⁸

Methods

Study Setting

This cohort study included data from the DHNA database in which all patients presenting with a first primary HNC are prospectively registered by trained staff. The DHNA is maintained by the Dutch Institute for Clinical Auditing, where data verification processes are guaranteed. ¹⁹ Approval for the research proposal was granted by the Institutional Review Board at Erasmus Medical Center, Rotterdam, the Netherlands, confirming exemption from the Medical Research Involving Human Subjects Act (MEC‐2022‐0816).

Population

All OCC patients who were surgically treated with curative intent between 2018 and 2021 were included. Carcinoma in situ and clinical T0 tumors were excluded. Previous literature and a study on the same cohort have indicated that neck dissection and reconstructive surgery are significantly associated with an increased risk of surgical complications. ²⁰ , ²¹ , ²² , ²³ Therefore, the cohort was stratified in a local resection (transoral resection without reconstruction) and an extensive resection group (including neck dissection and/or free or pedicled flap).

Primary Outcome

The primary outcome was the association between textbook outcome and survival. The criteria for textbook outcome were based on previous literature ¹⁰ , ¹⁷ and the expert opinion of the multidisciplinary DHNA scientific committee. Textbook outcome was defined as the absence of (1) 30‐day mortality, (2) hospital readmission after discharge, (3) prolonged length of hospital stay (>7 days for local and >21 days for extensive resections), (4) severe surgical complications (Clavien‐Dindo [CD] grade III or higher), ²⁴ (5) a definitive surgical margin of <1 mm, (6) and a lymph node yield <18 per side (only extensive resection). ²⁵ The lymph node yield was included to assess the quality of the performed neck dissection and pathological assessment as the DHNA population includes elective and therapeutic neck dissections that are selective, modified, or radical. The 18‐node cutoff has been previously described as a quality metric and is of prognostic impact. ²⁵ , ²⁶ , ²⁷ , ²⁸ OS and DFS were determined 2 years after the date of primary resection.

Variables and Definitions

Included case‐mix variables are unchangeable characteristics on the patient or tumor level that reflect the disease burden of the hospital population. The following case‐mix variables were selected from the DHNA database: sex, age, body mass index (BMI, kg/m²), alcohol and smoking history, World Health Organization (WHO) performance score, American Society of Anaesthesiologists (ASA) score, histology type, cTN‐classification based on the 8th edition, and subsite within the oral cavity based on the ICD‐O‐3 code (tongue, gum, floor of mouth, and other). ²⁹ , ³⁰ A comorbidity score could not be included in case‐mix correction because data in the DHNA during the study period were missing in different proportions across hospitals and, therefore, considered not at random. Additionally, data on the need for adjuvant therapy with radiotherapy or chemoradiation were extracted.

Statistical Analysis

Statistical analyses were performed using R version 4.2. Continuous variables were displayed as mean with standard deviation or median with interquartile range based on the distribution. A P‐value of less than .05 was considered statistically significant. Multiple imputation was performed to account for missing data using the mice package. ³¹ Imputation for the survival data was performed following the Nelson‐Aalen method. ³² The percentage of patients that met the separate criteria and the cumulative percentage of textbook outcome were calculated.

Time‐to‐event analysis was performed for OS and DFS. To prevent immortal time bias, patients who deceased within 30 days after surgery were excluded. Kaplan‐Meier curves were stratified for obtaining the textbook outcome, and the P‐values were calculated using the log‐rank test. Cox multivariable regression analysis was performed to calculate the adjusted hazard ratio (aHR) for the textbook outcome on OS and DFS with correction for confounders.

The possible existence of hospital variation in textbook outcome as a metric for quality of care was investigated using funnel plots with correction for case‐mix variables. Associations between textbook outcome and case‐mix variables were assessed using univariate and multivariate logistic regression analysis. All case‐mix variables were incorporated in the case‐mix correction model when there were sufficient events, following an assessment for multicollinearity. Multicollinearity was evaluated using the variance inflation factor (VIF) and was deemed absent when the VIF was less than 3.0. ⁸ To adjust for case‐mix, all available variables were entered in a multivariable logistic regression model to calculate the expected (E) textbook outcome of a hospital. Then, the ratio between the hospital's observed (O) and expected (O/E) textbook outcomes was calculated. An O/E ratio >1 indicates that a hospital performed above expectation based on the estimated predicted probability for achieving a textbook outcome. Hospital variation was visualized using funnel plots of the uncorrected and case‐mix corrected textbook outcome rates. ⁵

Results

Study Population

From the DHNA database, 2266 OCC patients could be included (Figure 1). Local resection was performed in 1039 patients, of which 81.1% (n = 843) met textbook outcome criteria (Table 1). The proportions of tongue tumors, SCC tumors, and cT1‐classification were significantly higher in the textbook outcome group. Extensive resection was performed in 1227 patients, 46.9% (n = 575) of whom reached textbook outcome. Patients who obtained a textbook outcome after extensive resection had a higher BMI, lower ASA score, and more cT2 and tongue tumors were observed in this group. Both for local and extensive resection, the criterion that occurred the least often was 30‐day mortality (0.2% and 1.4%, respectively), and the criterion that was scored most was resection margins <1 mm (11.6% and 18.9%, respectively, Figure 2).

Figure 1.

Flowchart for patient selection from the Dutch Head and Neck Audit (DHNA) database.

Table 1.

Patient and Tumor Characteristics (Case‐Mix) of Patients Undergoing Local and Extensive Resections for Oral Cavity Cancer in the Netherlands (2018‐2021)

	Local resection			Extensive resection
Patient and tumor characteristics	No TO	TO	P‐valuea	No TO	TO	P‐valuea
N	196	843		652	575
Sex
Male	86 (44%)	412 (49%)	.2	375 (58%)	340 (59%)	.6
Female	110 (56%)	431 (51%)		277 (42%)	235 (41%)
Age, y
Median (IQR)	70 (59‐78)	67 (58‐75)	.13	67 (60‐75)	66 (58‐74)	.12
<67	90 (46%)	408 (48%)	.5	313 (48%)	296 (51%)	.2
≥67	106 (54%)	435 (52%)		339 (52%)	279 (49%)
BMI, kg/m2
Median (IQR)	25 (23‐29)	26 (23‐29)	.3	25 (22‐28)	25 (23‐28)	.003
<25	87 (44%)	332 (39%)	.3	362 (56%)	268 (47%)	.002
≥25	102 (52%)	465 (55%)		286 (44%)	306 (53%)
Unknown	7 (3.6%)	46 (5.5%)		4 (0.6%)	1 (0.2%)
Smoking use
No history	58 (30%)	270 (32%)	.6	123 (19%)	135 (23%)	.14
Former or current	129 (66%)	525 (62%)		511 (78%)	425 (74%)
Unknown	9 (4.6%)	48 (5.7%)		18 (2.8%)	15 (2.6%)
Alcohol use
No history	31 (16%)	180 (21%)	.13	84 (13%)	78 (14%)	.6
Former or current	146 (74%)	567 (67%)		531 (81%)	457 (79%)
Unknown	19 (9.7%)	96 (11%)		37 (5.7%)	40 (7.0%)
WHO status
WHO 0‐1	125 (64%)	573 (68%)	.4	461 (71%)	415 (72%)	.069
WHO 2‐4	18 (9.2%)	58 (6.9%)		61 (9.4%)	34 (5.9%)
Unknown	53 (27%)	212 (25%)		130 (20%)	126 (22%)
ASA score
ASA 1‐2	125 (64%)	536 (64%)	>.9	396 (61%)	388 (67%)	.018
ASA 3‐4	51 (26%)	218 (26%)		248 (38%)	176 (31%)
Unknown	20 (10%)	89 (11%)		8 (1.2%)	11 (1.9%)
Histology
SCC	142 (72%)	757 (90%)	<.001	619 (95%)	559 (97%)	.055
Non‐SCC	54 (28%)	86 (10%)		32 (4.9%)	16 (2.8%)
Unknown	‐	‐		1 (0.2)	‐
cT‐classification
T1	104 (53%)	565 (67%)	<.001	66 (10%)	61 (11%)	<.001
T2	58 (30%)	233 (28%)		206 (32%)	244 (42%)
T3	6 (3.1%)	12 (1.4%)		160 (25%)	111 (19%)
T4	28 (14%)	33 (3.9%)		220 (34%)	159 (28%)
cN‐classification			.15			.6
Nx	2 (1.0%)	1 (0.1%)		6 (0.9%)	3 (0.5%)
N0	193 (98%)	838 (99%)		432 (66%)	364 (63%)
N1‐N2a	‐	2 (0.2%)		92 (14%)	88 (15%)
N2b‐N3	1 (0.5%)	2 (0.2%)		122 (19%)	120 (21%)
Subsite oral cavity
Tongue	58 (30%)	483 (57%)	<.001	225 (35%)	243 (42%)	.014
Gum	29 (15%)	92 (11%)	.2	155 (24%)	133 (23%)	.6
Floor of mouth	34 (17%)	103 (12%)		151 (23%)	98 (17%)
Other subsites	75 (39%)	165 (20%)		121 (19%)	101 (18%)
Treatment
Surgery	132 (67%)	755 (90%)	<.001	255 (39%)	245 (43%)	<.001
Surgery with RT	61 (31%)	78 (9.3%)		276 (42%)	275 (48%)
Surgery with CRT	3 (1.5%)	10 (1.2%)		121 (19%)	55 (9.6%)

Abbreviations: ASA, American Society of Anaesthesiologists; BMI, body mass index; CRT, chemoradiation; IQR, interquartile range; RT, radiotherapy; SCC, squamous cell carcinoma; TO, textbook outcome; WHO, World Health Organization.

^a Pearson's chi‐square test, Wilcoxon rank sum test, and Fisher's exact test.

Figure 2.

The percentage of criteria met and the cumulative percentage of textbook outcome. TO, textbook outcome.

Population Characteristics and Textbook Outcome

For local resection, non‐SCC (odds ratio [OR] 0.52) and cT3‐T4 tumors (OR 0.52) were significantly associated with a decreased odds of obtaining a textbook outcome (Table 2). Patients were more likely to obtain a textbook outcome after extensive surgery in case of a BMI ≥ 25 kg/m² (OR 1.49). The chance of obtaining a textbook outcome after extensive surgery was lower when female (OR 0.72), WHO status ≥ 2 (OR 0.49), and cT3‐T4 (OR 0.19). Both for local and extensive surgery, patients were less likely to obtain textbook outcomes when the tumor was located on the floor of mouth (OR local 0.33 and extensive 0.49) or other subsites (OR local 0.45 and extensive 0.56) compared to tongue tumors. Patients that met textbook outcome criteria received adjuvant therapy significantly less often (OR local 0.30 and extensive 0.48).

Table 2.

Imputed (Multiple Imputation) Multivariable Logistic Regression Analyses, Showing the Association of Patient and Tumor Characteristics With Textbook Outcome After Oral Cavity Cancer Resection in the Netherlands

		Local resection			Extensive resection
Case‐mix variables		OR	95% CI	P‐value	OR	95% CI	P‐value
Sex	Male	‐	‐		‐	‐
	Female	0.77	0.54, 1.09	.14	0.72	0.53, 0.99	.041
Age	<67 y	‐	‐		‐	‐
	≥67 y	0.87	0.61, 1.24	.44	0.89	0.65, 1.21	.45
Body mass index	<25 kg/m2	‐	‐		‐	‐
	≥25 kg/m2	1.17	0.82, 1.65	.39	1.49	1.10, 2.01	.009
Smoking history	No history	‐	‐		‐	‐
	Former or current	1.11	0.74, 1.67	.62	0.80	0.54, 1.17	.25
Alcohol history	No history	‐	‐		‐	‐
	Former or current	0.64	0.39, 1.06	.081	1.50	0.91, 2.46	.11
WHO status	0‐1	‐	‐		‐	‐
	≥2	0.54	0.28, 1.03	.061	0.49	0.24, 1.00	.050
ASA score	I‐II	‐	‐		‐	‐
	III‐IV	0.93	0.61, 1.43	.74	0.72	0.51, 1.01	.059
Histology	SCC	‐	‐		‐	‐
	Non‐SCC	0.52	0.32, 0.84	.008	0.67	0.28, 1.63	.38
cT‐classification	T1‐T2	‐	‐		‐	‐
	T3‐T4	0.52	0.29, 0.94	.029	0.19	0.13, 0.27	<.001
cN‐classification	Nx‐N0	‐	‐		‐	‐
	N1‐N3	1.95	0.20, 18.6	.56	0.96	0.68, 1.36	.84
Subsite oral cavity	Tongue	‐	‐		‐	‐
	Gum	0.57	0.32, 1.02	.057	1.30	0.85, 1.98	.23
	Floor of mouth	0.33	0.20, 0.55	<.001	0.49	0.32, 0.75	<.001
	Other subsite	0.45	0.28, 0.71	<.001	0.56	0.35, 0.89	.013
Treatment	Surgery	‐	‐		‐	‐
	Surgery and (C)RT	0.30	0.19, 0.46	<.001	0.48	0.35, 0.67	<.001

Abbreviations: ASA, American Society of Anaesthesiologists; CI, confidence interval; (C)RT, chemo)radiation; OR, odds ratio; SCC, squamous cell carcinoma; WHO, World Health Organization.

Textbook Outcome and Survival

Kaplan‐Meier curves indicated that 2‐year OS and DFS were higher in patients meeting textbook outcome criteria after local and extensive resection (Figure 3). The aHR in multivariable Cox regression analysis for the textbook outcome after local resection was 0.55 (CI 0.36‐0.82) for OS and 0.70 (CI 0.47‐1.05) for DFS (Table 3). In extensive resection, the aHRs for OS and DFS were 0.61 (CI 0.48‐0.78) and 0.69 (CI 0.54‐0.88), respectively. Full results of the Cox regression analyses are presented in Supplement [Link], [Link], available online.

Figure 3.

Kaplan‐Meier curves for 2‐year overall and disease‐free survival outcomes in local and extensive resection. Patients with missing data on overall survival were excluded from the analysis. n = 42 (4.0%) in local resection, n = 24 (2.0%) in extensive resection. P‐values are calculated using the log‐rank test.

Table 3.

Imputed (Multiple Imputation) Multivariable Cox Regression ^a Analyses for Textbook Outcome on 2‐Year Overall and Disease‐Free Survival

		Local resection			Extensive resection
Two‐year outcome		aHR	95% CI	P‐value	aHR	95% CI	P‐value
Overall survival	No TO	‐			‐
	TO	0.55	0.36, 0.82	.004	0.61	0.48, 0.78	<.001
Disease‐free survival	No TO	‐			‐
	TO	0.70	0.47, 1.05	.085	0.69	0.54, 0.88	.002

Abbreviations: aHR, adjusted hazard ratio; TO, textbook outcome.

^a Patients with missing data on overall survival were excluded from analysis (n = 42 [4.0%] in local resection, n = 24 [2.0%] in extensive resection). The hazard ratio is adjusted (aHR) for sex, age, body mass index, smoking and alcohol history, World Health Organization status, American Society of Anaesthesiologists score, histology, cTN‐classification, subsite in the oral cavity, and adjuvant therapy. Full results of the Cox regression analyses are presented in Supplement [Link], [Link], available online.

Hospital Variation in Textbook Outcome

Unadjusted hospital results of textbook outcome after local resection ranged from 64.3% to 97.5% (Figure 4) with no outlier hospitals. After case‐mix correction, performance for all hospitals remained between the CIs. For extensive resection, hospital performance on textbook outcome varied from 32.3% to 75.5%, and two hospitals performed outside the 95% CI. Results of these two hospitals were between the CIs after correction for case‐mix variables.

Figure 4.

Funnel plots showing the hospital variation in textbook outcome rates before and after case‐mix correction for local and extensive surgery. CI, confidence interval.

Discussion

This study evaluated a composite outcome measure, the textbook outcome, after OCC surgery in a national cohort of 2266 patients. Achieving the textbook outcome was associated with improved 2‐year OS and DFS. To assess the quality of care, interhospital differences in textbook outcome were evaluated. After correction for case‐mix variables, of which the impact differed between local and extensive resection, no significant interhospital variation in textbook outcome remained.

Our findings broadly align with previous studies yet highlight key differences, mainly in patient inclusion criteria. One textbook outcome study was performed in one of the Dutch HNC hospitals on a preceding cohort of 392 primary HNC patients. ¹⁷ Their definition of textbook outcome after surgery was treatment initiation within 30 days, no complications, resection margins >5 mm, a lymph node radio of ≤7%, and no 30‐day mortality. Overall textbook outcome after surgery was 29.3%, but this lowered to 9.4% in the case of excision with neck dissection and reconstructive surgery. This study's lower textbook outcome rate is mainly explained by the included 30‐day treatment interval and margin cutoff at >5 mm. The 30‐day cutoff is commonly used in the Netherlands but is less frequently applied internationally and is more appropriate when evaluating a “textbook process” instead of an outcome. ³³ , ³⁴ Adhering to the 5‐mm cutoff has been discussed in the DHNA scientific committee. The Royal College of Pathologists defines a clear margin as >5 mm between the tumor and resection border. ³⁵ Still, the 1‐mm cutoff was included in the textbook outcome as evidence exists that margins of 1 to 5 mm can be accepted to obtain good OS and DFS rates, margins >5 mm can be anatomically unattainable or clinically negligible, and other surgical oncologic disciplines audit margins <1 mm. ⁷ , ⁹ , ³⁶ , ³⁷ , ³⁸ , ³⁹ , ⁴⁰ The second OCC textbook outcome study reports on 386 Taiwanese OCC patients who underwent both a neck dissection and reconstruction. ¹⁰ Textbook outcome was defined as the absence of readmission <30 days, emergency room visit within 3 days, length‐of‐stay > 22 days, a LNY < 29 per side, and positive surgical margins. Textbook outcome was obtained in 35.0% and was associated with improved 5‐year OS. The same authors performed an investigation of prognostic factors for 1‐year mortality in 397 Taiwanese OCC patients who underwent resection with neck dissection. ¹³ Textbook outcome from their previous study was modified by the exclusion of emergency room visits in 3 days. Modified textbook outcome was an independent prognostic factor for early death.

Our study is the first to assess national survival outcomes after the textbook outcome for OCC surgery. This comprehensive approach provides a robust evaluation of hospital performance and the utility of textbook outcome as a quality indicator. Included quality metrics for the definition of textbook outcome are internationally used to facilitate the use of textbook outcome by other institutes or quality registries. A limitation is that our definition of textbook outcome focused solely on surgical outcomes, as data on adverse events following systemic therapies and radiotherapy are not yet available in the DHNA. This restricts the generalizability of the textbook outcome to patients undergoing multimodal treatments. Medical complications were not included in the textbook outcome, though these frequently occur in the HNC population. ⁴¹ Unfortunately, the comorbidity score and socioeconomic status could not be included as covariates. The DHNA collaborators are working on improving data completeness, but strict Dutch privacy laws complicate linking with other databases. Furthermore, as patients are registered as‐treated, possible selection bias can be introduced. Overall, the large sample size and national coverage help mitigate registration bias.

In this study, the use of textbook outcome as quality indicator for clinical auditing and the need for case‐mix correction were assessed. After case‐mix correction, no significant interhospital variation remained. Especially in extensive resections, this did influence individual hospital results, indicating the need for case‐mix correction here. If local and extensive resections were grouped for textbook outcome reporting, results should be corrected for extensive surgery because this proportion differed significantly between hospitals (P < .001, Supplement S2, available online). All hospitals obtained a higher result for the textbook outcome in local surgery compared to extensive surgery (Supplement S3, available online). For benchmarking purposes, a minimal impact of case‐mix is preferable, as this enhances the likelihood that observed differences between hospitals reflect variations in quality of care rather than differences in patient demographics. The lack of outlier hospitals after case‐mix correction could be due to the longstanding centralization of HNC care in the Netherlands. In countries or cancer networks where HNC is not centralized, more hospital variation could exist.

Quality improvement plans at the hospital level can potentially improve survival outcomes when focusing on the textbook outcome. There is much room for improvement in obtaining better tumor‐free resection margins, as most patients fell out due to <1 mm margin for local and extensive resection (Supplement S4, available online). This is why multicenter studies on the implementation of ultrasound‐guided resections have started in several of the participating hospitals that provide HNC care in the Netherlands. ⁴² , ⁴³ , ⁴⁴ Females were less likely, and patients with a BMI ≥ 25 kg/m² were more likely to obtain a textbook outcome after extensive resection. Prior studies both confirm and contradict an increased risk of complications or adverse pathological outcomes in females, suggesting that further research is needed to explain this finding. ⁴⁵ , ⁴⁶ , ⁴⁷ , ⁴⁸ Research examining the relationship between elevated BMI and postoperative outcomes in HNC surgery presents conflicting findings. ⁴⁹ , ⁵⁰ No comorbidity score could be included in the case‐mix correction, but a BMI ≥ 25 kg/m² could be significant as a substitute for other comorbidities. Our results suggest that patients with a low BMI are more fragile and therefore are less likely to obtain a textbook outcome. The group of cT3‐T4 and cN1‐3 tumors in the local resection group was notable as these often require a neck dissection and/or reconstruction. The five patients with clinically involved nodes underwent sentinel lymph node biopsy or radiation of the neck. These cT3‐T4 patients were either verrucous carcinomas or maxilla tumors that did not require reconstruction and underwent sentinel lymph node biopsy.

Applying textbook outcome in clinical practice and auditing has relevant implications for quality improvement. Due to the composite nature of the textbook outcome, hospitals gain local insights into their specific areas for improvement while being able to compare their overall performance to the national benchmark. When the incidence of quality indicators, such as mortality, is low, it becomes challenging or even impossible to differentiate clinically meaningful differences due to statistical uncertainty. ⁵¹ , ⁵² Low‐volume indicators, therefore, can require extended data collection periods before accurate real‐time feedback can be provided. As a short‐term composite measure, the textbook outcome provides a more comprehensive and reliable metric for assessing real‐time hospital performance, offering a better foundation for clinical auditing based on daily clinical practices. ⁵¹ Within the monitoring system of the DHNA, feedback on the textbook outcome can be provided to all hospitals performing HNC care. Hospital results can be reported on dashboards so surgeons can compare their textbook outcome rates with other hospitals. Moreover, round table meetings are organized annually, where the data are openly discussed to identify best practices. Though the textbook outcome is a short‐term outcome indicator, the association with OS and DFS has been demonstrated in this study. Moreover, the need for adjuvant therapy was lower in patients that met textbook outcome criteria. Stimulating hospitals to improve textbook outcome results is therefore expected to improve clinical and survival outcomes.

Future studies should expand the concept of textbook outcome in other HNC subsites and include nonsurgically treated patients to provide a comprehensive HNC indicator. Publications on implementing quality improvement plans focused on surgical complications and resection margins can aid hospitals aiming to improve their hospital results on these outcomes of surgery. Studies should also align definitions and textbook outcome parameters or at least include a sensitivity analysis for various definitions to assess their impact. A “textbook process” should be evaluated to assess process indicators such as waiting times for treatment and adjuvant therapy, malnutrition screening, or geriatric assessment. ³³ , ³⁴ , ⁵³

In conclusion, achieving the textbook outcome is strongly linked to improved OS and DFS, highlighting its importance as a short‐term composite quality indicator. In this centralized HNC care system in the Netherlands, no significant hospital variation in textbook outcome was observed. Correction for case‐mix variables for textbook outcome is necessary for extensive resections but of limited influence for local resection. The separate outcomes that influenced the hospital's textbook outcome score did differ, indicating room for improvement.

Author Contributions

Hanneke Doremiek van Oorschot, Conceptualization, data curation, data extraction, statistical analysis, data review, drafting of the manuscript, interpretation of the results, manuscript review, approval, reading of the final manuscript. Dominique Valerie Clarence de Jel, Conceptualization, data curation, data extraction, statistical analysis, data review, drafting of the manuscript, interpretation of the results, manuscript review, approval, reading of the final manuscript. Jose Angelito Hardillo, Conceptualization, data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Robert J. J. van Es, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Guido B. van den Broek, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Robert Paul Takes, Data curation, interpretation of the results, manuscript review, approval, Reading of the final manuscript. Gyorgy Bela Halmos, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Richard Dirven, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Martin Lacko, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Lauretta Anna Alexandra Vaassen, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Jan‐Jaap Hendrickx, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Marjolijn Abigal Eva‐Maria Oomens, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Hossein Ghaeminia, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Jeroen C. Jansen, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Annemarie Vesseur, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Rolf Bun, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Leonora Q. Schwandt, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Christiaan A. Krabbe, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Thomas J. W. Klein Nulent, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Alexander J. M. van Bemmel, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Reinoud J. Klijn, Data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript. Robert Jan Baatenburg de Jong, Conceptualization, data curation, interpretation of the results, manuscript review, approval, reading of the final manuscript.

Disclosures

Competing interests

The authors declare there was no conflict of interest.

Funding source

None.

Supporting information

Supporting Information.

Supporting Information.

Supporting Information.

Supporting Information.

Supporting Information.

Data Availability Statement

Data are accessible upon request at www.dica.nl/dhna.