Association of Compliance With Process-Related Quality Metrics and Improved Survival in Oral Cavity Squamous Cell Carcinoma

Identifying Opportunities to Deliver High-Quality Cancer Care Across a Health System: A Clinical Responsibility

OBJECTIVE

We examined process-related quality metrics for oral squamous cell carcinoma (OSCC) depending on treating facility type across a health system and region.

STUDY DESIGN

Retrospective in accordance with Strengthening the Reporting of Observational Studies in Epidemiology guidelines.

SETTING

Single health system and region.

METHODS

Patients with OSCC diagnosed between 2012 and 2018 were identified from tumor registries of 6 hospitals (1 academic and 5 community) within a single health system. Patients were categorized into 3 care groups: (1) solely at the academic center, (2) solely at community facilities, and (3) combined care at academic and community facilities. Primary outcome measures were process-related quality metrics: positive surgical margin rate, lymph node yield (LNY), adjuvant treatment initiation ≤6 weeks, National Comprehensive Cancer Network (NCCN)-guideline adherence.

RESULTS

A total of 499 patients were included: 307 (61.5%) patients in the academic-only group, 101 (20.2%) in the community-only group, and 91 (18.2%) in the combined group. Surgery at community hospitals was associated with increased odds of positive surgical margins (11.9% vs 2.5%, odds ratio [OR]: 47.73, 95% confidence interval [CI]: 11.2-275.86, P < .001) and lower odds of LNY ≥ 18 (52.8% vs 85.9%, OR: 0.15, 95% CI: 0.07-0.33, P < .001) relative to the academic center. Compared with the academic-only group, odds of adjuvant treatment initiation ≤6 weeks were lower for the combined group (OR: 0.30, 95% CI: 0.13-0.64, P = .002) and odds of NCCN guideline-adherent treatment were lower in the community only group (OR: 0.35, 95% CI: 0.18-0.70, P = .003).

CONCLUSION

Quality of oral cancer care across the health system and region is comparable to or better-than national standards, indicating good baseline quality of care. Differences by facility type and fragmentation of care present an opportunity for bringing best in-class cancer care across an entire region.

Insurance Disparities in Quality of Care Among Patients With Head and Neck Cancer

Importance

Significant insurance status disparities have been demonstrated in head and neck cancer (HNC) outcomes. The effects of insurance status on HNC outcomes may be explained by differential access to high-quality care.

Objective

To evaluate the association of insurance status with the quality of the treating hospital and receipt of guideline-compliant care among patients with HNC.

Design, Setting, and Participants

This retrospective cohort study of data from the California Cancer Registry dataset linked with discharge records and hospital characteristics from the California Department of Health Care Access and Information included adult patients with HNC diagnosed between January 1, 2010, and December 31, 2019. Data were analyzed from May 10, 2023, to March 25, 2024.

Exposures

Insurance status: commercial, Medicare, Medicaid, uninsured, other, or unknown.

Main Outcomes and Measures

Quality of the treating hospital (tertiles), receipt of National Comprehensive Cancer Network guideline-compliant care, and overall survival.

Results

A total of 23 933 patients (mean [SD] age, 64.8 [12.3] years; 75.3% male) met the inclusion criteria. Treatment in top-tertile hospitals (hazard ratio, 0.87; 95% CI, 0.79-0.95) was associated with improved overall survival compared with treatment in bottom-tertile hospitals. Medicare (odds ratio [OR], 0.78; 95% CI, 0.73-0.84), Medicaid (OR, 0.60; 95% CI, 0.54-0.66), and uninsured (OR, 0.38; 95% CI, 0.29-0.49) status were associated with lower likelihood of treatment in high-quality hospitals compared with commercial insurance. Among patients with advanced disease, Medicaid (OR, 0.72; 95% CI, 0.62-0.83) and uninsured (OR, 0.64; 95% CI, 0.44-0.93) patients were less likely to receive dual-modality therapy. Among patients with surgically resected advanced disease, Medicaid coverage (OR, 0.73; 95% CI, 0.58-0.93) was associated with lower likelihood of receiving adjuvant radiotherapy.

Conclusions and Relevance

This study found significant insurance disparities in quality of care among patients with HNC. These findings highlight the need for continued health insurance reform in the US to improve the quality of insurance coverage, in addition to expanding access to health insurance.

Time-to-Treatment Delays and Their Prognostic Implications in Pharyngeal Cancer-An Exploratory Analysis in Western Romania

BACKGROUND

Diagnosis and treatment for pharyngeal cancer are decisive in determining prognosis. Diagnosis delays are frequent, representing a significant cause of avoidable mortality, and an important factor in subpar survival across the continuous HNC care delivery.

METHODS

The present study represents a retrospective analysis of medical records from Western Romania, which included 180 patients, to evaluate the impact of time-to-treatment delay on patients diagnosed with pharyngeal cancer. The data analyses were performed using the Kaplan-Meier method R (version 3.6.3) packages, including tidyverse, final-fit, mcgv, survival, stringdist, janitor, and Hmisc.

RESULTS

The mean days from diagnosis until the end of treatment were higher for the nasopharynx group. Cox regression analysis regarding diagnosis to treatment duration categories showed an increased risk mortality by 3.11 times (95%CI: 1.51-6.41, p = 0.0021) with a Harrell's C-index of 0.638 (95%CI: 0.552-0.723). The hypopharynx and oropharynx locations increased risk mortality by 4.59 (95%CI: 1.55-13.55) and 5.49 times (95%CI: 1.79-16.81) compared to the nasopharynx location.

CONCLUSIONS

The findings of this study led to the conclusion that it seems there is a trend of mortality risk for oropharynx and hypopharynx cancers due to delays in the time to treatment over 70 days, standing as a basis for further research as there is an imperative need for prospective multicenter studies.

Opportunistic pathogen Porphyromonas gingivalis targets the LC3B-ceramide complex and mediates lethal mitophagy resistance in oral tumors

Mechanisms by which Porphyromonas gingivalis (P. gingivalis) infection enhances oral tumor growth or resistance to cell death remain elusive. Here, we determined that P. gingivalis infection mediates therapeutic resistance via inhibiting lethal mitophagy in cancer cells and tumors. Mechanistically, P. gingivalis targets the LC3B-ceramide complex by associating with LC3B via bacterial major fimbriae (FimA) protein, preventing ceramide-dependent mitophagy in response to various therapeutic agents. Moreover, ceramide-mediated mitophagy is induced by Annexin A2 (ANXA2)-ceramide association involving the E142 residue of ANXA2. Inhibition of ANXA2-ceramide-LC3B complex formation by wild-type P. gingivalis prevented ceramide-dependent mitophagy. Moreover, a FimA-deletion mutant P. gingivalis variant had no inhibitory effects on ceramide-dependent mitophagy. Further, 16S rRNA sequencing of oral tumors indicated that P. gingivalis infection altered the microbiome of the tumor macroenvironment in response to ceramide analog treatment in mice. Thus, these data provide a mechanism describing the pro-survival roles of P. gingivalis in oral tumors.

Factors Associated with Head and Neck Cancer Postoperative Radiotherapy Delays: A Systematic Review and Meta-analysis

OBJECTIVE

Initiating postoperative radiotherapy (PORT) within 6 weeks of surgery for head and neck squamous cell carcinoma (HNSCC) is included in the National Comprehensive Cancer Network Clincal Practice Guidelines and is a Commission on Cancer quality metric. Factors associated with delays in starting PORT have not been systematically described nor synthesized.

DATA SOURCES

PubMed, Scopus, and CINAHL.

REVIEW METHODS

We included studies describing demographic characteristics, clinical factors, or social determinants of health associated with PORT delay (>6 weeks) in patients with HNSCC treated in the United States after 2003. Meta-analysis of odds ratios (ORs) was performed on nonoverlapping datasets.

RESULTS

Of 716 unique abstracts reviewed, 21 studies were included in the systematic review and 15 in the meta-analysis. Study sample size ranged from 19 to 60,776 patients. In the meta-analysis, factors associated with PORT delay included black race (OR, 1.46, 95% confidence interval [CI]: 1.28-1.67), Hispanic ethnicity (OR, 1.37, 95% CI, 1.17-1.60), Medicaid or no health insurance (OR, 2.01, 95% CI, 1.90-2.13), lower income (OR, 1.38, 95% CI, 1.20-1.59), postoperative admission >7 days (OR, 2.92, 95% CI, 2.31-3.67), and 30-day hospital readmission (OR, 1.37, 95% CI, 1.29-1.47).

CONCLUSION

Patients at greatest risk for a delay in initiating guideline-adherent PORT include those who are from minoritized communities, of lower socioeconomic status, and experience postoperative challenges. These findings provide the foundational evidence needed to deliver targeted interventions to enhance equity and quality in HNSCC care delivery.

Lymph node level ratio as a predictor of survival in oral cavity squamous cell carcinoma

OBJECTIVE

To evaluate whether nodal yields and ratios based on level serves as prognostic indicators in patients with oral cavity squamous cell carcinoma undergoing neck dissection.

MATERIALS AND METHODS

A retrospective analysis of 342 patients with oral cavity squamous cell carcinoma treated surgically between 1998 and 2017 were included.Demographics and clinicopathologic data were collated. Disease specific survival and overall survival were analyzed via Kaplan-Meier method and log-rank test as well as univariable and multivariable Cox models.

RESULTS

Total nodal yield is associated with improved overall and disease specific survival (p < 0.01). Total positive nodal yield (p < 0.01), positive nodal ratio per level (p < 0.001), and identification of <4 lymph nodes/level (p < 0.001) are associated with worse disease specific survival and overall survival. A ratio of at least 4 lymph nodes/level dissected yields the maximal hazard ratio on for both disease specific and overall survival optimizes the Kaplan-Meier split between survival groups. After controlling for sex, age, margin status, disease stage, extranodal extension, perineural invasion, and lymphovascular invasion as fixed covariates in the Cox models, a nodal level ratio of 4 lymph nodes/level provides hazard ratio (95% CI) of 3.59 (1.69, 7.60); p < 0.0006) for disease free survival and 2.90 (1.54, 5.46; p < 0.001) for overall survival.

CONCLUSION

Nodal level ratio of < 4 lymph nodes/level is associated with worse disease specific and overall survival in oral cavity squamous cell carcinoma. This level-specific metric may prove useful qualitatively and in predicting survival in oral cavity cancer with broader utility to address variations in levels of neck dissection performed.

Improving Outpatient Follow-Up Rates for New In-Hospital Consults

OBJECTIVE(S)

This investigation aimed to define the rate of outpatient follow-up after in-hospital consultation, identify factors associated with establishing care, and evaluate an alternative scheduling process to improve outpatient adherence.

METHODS

Two-phase, prospective study at an academic, tertiary-care institution from March 2020 to August 2022. First, all patients not previously known to our practice encountered via inpatient consult who warranted outpatient follow-up were prospectively captured. Logistic regression analysis was used to identify demographic, disease, and practice factors predictive of follow-up. Second, a randomized control trial was performed to validate the effects of pre-assigning appointments prior to discharge.

RESULTS

Six hundred subjects were included in the final study cohort; 500 in phase-one, and 100 randomized during phase-two. In the phase-one cohort, 54% (n = 272) were lost to follow-up. Multivariate analysis showed increased odds of outpatient follow-up when appointments were pre-assigned before discharge (odds ratio [OR]: 3.69 [95% confidence interval [CI]: 2.29-5.96], p < 0.001), the primary reason for hospitalization was ENT and consult-related (OR: 3.29 [1.92-5.64], p < 0.001), and the diagnosis was one of Oncology (OR: 1.93 [1.02-3.69], p = 0.045) or Pediatrics (OR: 3.36 [1.41-7.98], p = 0.006) subspecialties. During phase-two, subjects randomized for pre-assigned appointments had higher outpatient follow-up (82%) compared to the control group (20%) (p < 0.001).

CONCLUSION

Hospital-based consultations represent an important referral pathway for new patients. Disease characteristics may identify patients less likely to follow-up upon discharge. Appointment scheduling protocols, including pre-assigning appointments, are modifiable targets for improving adherence to care. Laryngoscope, 133:2540-2545, 2023.

Eugene Nicholas Myers' Lecture on Head and Neck Cancer, 2020: The Surgeon as a Prognostic Factor in Head and Neck Cancer Patients Undergoing Surgery

This paper is a transcript of the 29 th Eugene N. Myers, MD International Lecture on Head and Neck Cancer presented at the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) in 2020. By the end of the 19 th century, the survival rate in treated patients was 10%. With the improvements in surgical techniques, currently, about two thirds of patients survive for > 5 years. Teamwork and progress in surgical reconstruction have led to advancements in ablative surgery; the associated adjuvant treatments have further improved the prognosis in the last 30 years. However, prospective trials are lacking; most of the accumulated knowledge is based on retrospective series and some real-world data analyses. Current knowledge on prognostic factors plays a central role in an efficient treatment decision-making process. Although the influence of most tumor- and patient-related prognostic factors in head and neck cancer cannot be changed by medical interventions, some environmental factors-including treatment, decision-making, and quality-can be modified. Ideally, treatment strategy decisions should be taken in dedicated multidisciplinary team meetings. However, evidence suggests that surgeons and hospital volume and specialization play major roles in patient survival after initial or salvage head and neck cancer treatment. The metrics of surgical quality assurance (surgical margins and nodal yield) in neck dissection have a significant impact on survival in head and neck cancer patients and can be influenced by the surgeon's expertise. Strategies proposed to improve surgical quality include continuous performance measurement, feedback, and dissemination of best practice measures.

Machine learning methods applied to risk adjustment of cumulative sum chart methodology to audit free flap outcomes after head and neck surgery

We describe a risk adjustment algorithm to benchmark and report free flap failure rates after immediate reconstruction of head and neck defects. A dataset of surgical care episodes for curative surgery for head and neck cancer and immediate reconstruction (n = 1593) was compiled from multiple NHS hospitals (n = 8). The outcome variable was complete flap failure. Classification models using preoperative patient demographic data, operation data, functional status data and tumour stage data, were built. Machine learning processes are described to model free flap failure. Overall complete flap failure was uncommon (4.7%) with a non-statistical difference seen between hospitals. The champion predictive model had acceptable discrimination (AUROC 0.66). This model was used to risk-adjust cumulative sum (CuSUM) charts. The use of CuSUM charts is a viable way to monitor in a 'Live Dashboard' this quality metric as part of the quality outcomes in oral and maxillofacial surgery audit.

Head and neck cancers: Monitoring quality and reporting outcomes

INTRODUCTION

Head and neck cancers (HNC) require high level multidisciplinary care to achieve optimal outcomes. Reporting of quality indicators (QIs) has been instigated by some health services in an effort to improve quality of care. The aim of this study was to determine the quality of care provided to patients with HNC at a single institution by analysing compliance with QIs and to explore the feasibility and utility of collecting this data.

METHODS

This was a single institution retrospective chart review of all patients with squamous cell HNC at Townsville Hospital who were treated with curative intent between June 2011 and June 2019. Data was entered into a RedCap database and then exported to Stata V16 for analysis.

RESULTS

A total of 537 patients were included in the overall study, with six patients who had a synchronous non-HNC and two patients who received previous radiotherapy (RT) to the head and neck region excluded from the outcome analysis. Overall, compliance with pre-treatment, treatment and post-treatment QIs was high, with the exception of smoking cessation support (66%), post-treatment dental review and time to post-operative RT (33% of patients within 6 weeks). The 5-year overall survival was 69.4% (CI; 64-73.2%). The cumulative incidence of locoregional relapse for the overall study cohort was 18% (CI; 14.8-21.4%).

CONCLUSION

Collecting and evaluating quality metrics is feasible and helps identify areas for improvement. Centres treating HNC patients should strive towards monitoring quality against benchmarks and demonstrate transparency in outcome data.

Development and Evaluation of a Navigation-Based, Multilevel Intervention to Improve the Delivery of Timely, Guideline-Adherent Adjuvant Therapy for Patients With Head and Neck Cancer

PURPOSE

More than half of patients with head and neck squamous cell carcinoma (HNSCC) experience a delay initiating guideline-adherent postoperative radiation therapy (PORT), contributing to excess mortality and racial disparities in survival. However, interventions to improve the delivery of timely, equitable PORT among patients with HNSCC are lacking. This study (1) describes the development of NDURE (Navigation for Disparities and Untimely Radiation thErapy), a navigation-based multilevel intervention (MLI) to improve guideline-adherent PORT and (2) evaluates its feasibility, acceptability, and preliminary efficacy.

METHODS

NDURE was developed using the six steps of intervention mapping (IM). Subsequently, NDURE was evaluated by enrolling consecutive patients with locally advanced HNSCC undergoing surgery and PORT (n = 15) into a single-arm clinical trial with a mixed-methods approach to process evaluation.

RESULTS

NDURE is a navigation-based MLI targeting barriers to timely, guideline-adherent PORT at the patient, healthcare team, and organizational levels. NDURE is delivered via three in-person navigation sessions anchored to case identification and surgical care transitions. Intervention components include the following: (1) patient education, (2) travel support, (3) a standardized process for initiating the discussion of expectations for PORT, (4) PORT care plans, (5) referral tracking and follow-up, and (6) organizational restructuring. NDURE was feasible, as judged by accrual (88% of eligible patients [100% Blacks] enrolled) and dropout (n = 0). One hundred percent of patients reported moderate or strong agreement that NDURE helped solve challenges starting PORT; 86% were highly likely to recommend NDURE. The rate of timely, guideline-adherent PORT was 86% overall and 100% for Black patients.

CONCLUSION

NDURE is a navigation-based MLI that is feasible, is acceptable, and has the potential to improve the timely, equitable, guideline-adherent PORT.

Racial/Ethnic Disparities in Use of High-Quality Hospitals Among Oral Cancer Patients in California

OBJECTIVES/HYPOTHESIS

To examine racial/ethnic differences in use of high-quality hospitals in patients treated for oral cancer in California.

STUDY DESIGN

Retrospective cancer database cohort study.

METHODS

Data were extracted from the California Cancer Registry data set linked with discharge records and hospital characteristics from the California Office of Statewide Health Planning and Development, and with neighborhood characteristics from the California Neighborhoods Data System. The study cohort comprised adult patients with oral cavity malignancy diagnosed between 2004 and 2015. Principal component analysis was used to generate the composite oral cancer-specific hospital quality score. The impact of hospital quality on survival was assessed using Cox regression models with robust standard error using sandwich variance estimators. Poisson regression models with robust error variance were used to assess the association between race/ethnicity and use of high-quality hospitals.

RESULTS

Patients treated in hospitals ranked in the top quartile for quality had improved overall survival (hazard ratio 0.86, 95% confidence intervals [CI] 0.76-0.98), after adjusting for tumor stage, Charlson comorbidity score, neck dissection, radiotherapy, age, sex, race, and insurance status. Black patients (risk ratio 0.87, 95% CI 0.77-0.98) were less likely to be treated in high-quality hospitals compared with non-Hispanic White patients.

CONCLUSION

Treatment in high-quality hospitals is associated with improved survival for patients with oral cancer. However, black patients are less likely to be treated in high-quality hospitals compared with non-Hispanic white patients.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

The Synthetic Flavonoid Derivative GL-V9 Induces Apoptosis and Autophagy in Cutaneous Squamous Cell Carcinoma via Suppressing AKT-Regulated HK2 and mTOR Signals

Cutaneous squamous-cell carcinoma (cSCC) is one of most common type of non-black skin cancer. The malignancy degree and the death risk of cSCC patients are significantly higher than basal cell carcinoma patients. GL-V9 is a synthesized flavonoid derived from natural active ingredient wogonin and shows potent growth inhibitory effects in liver and breast cancer cells. In this study, we investigated the anti-cSCC effect and the underlying mechanism of GL-V9. The results showed that GL-V9 induced both apoptosis and autophagy in human cSCC cell line A431 cells, and prevented the growth progression of chemical induced primary skin cancer in mice. Metabolomics assay showed that GL-V9 potentially affected mitochondrial function, inhibiting glucose metabolism and Warburg effect. Further mechanism studies demonstrated that AKT played important roles in the anti-cSCC effect of GL-V9. On one hand, GL-V9 suppressed AKT-modulated mitochondrial localization of HK2 and promoted the protein degradation of HK2, resulting in cell apoptosis and glycolytic inhibition. On the other hand, GL-V9 induced autophagy via inhibiting Akt/mTOR pathway. Interestingly, though the autophagy induced by GL-V9 potentially antagonized its effect of apoptosis induction, the anti-cSCC effect of GL-V9 was not diluted. All above, our studies suggest that GL-V9 is a potent candidate for cSCC treatment.

The Efficacy of Low Postoperative Radiation Dose in Patients with Advanced Hypopharyngeal Cancer without High-Risk Factors

Objective

To evaluate the feasibility and efficacy of low postoperative radiotherapy (PORT) dose in patients with advanced hypopharyngeal squamous cell carcinoma (HPSCC) and identify prognostic factors in this group.

Patients and Methods

Between January 2013 and September 2015, 110 consecutive patients with HPSCC with no high-risk factors were treated postoperatively to 50 Gy (n=89), 56 Gy (n=12), and 60 Gy (n=9) in 2 Gy/fraction. Overall survival (OS), 3-year progression-free survival (PFS), 3-year loco-regional recurrence-free survival (LRFS), and treatment-related toxicities were analyzed.

Results

Median follow-up time was 40 months (range=6–75 months). The 3-year local-regional control (LRC) and 3-year neck control rate were 86.3% and 91.8%, respectively. The 3-year OS, PFS, and LRFS were 69.9%, 65.5%, and 80.5%, respectively. In a univariate analysis, T stage showed a significant correlation with improved OS, PFS, and LRFS (P=0.008, P=0.039, P=0.034). On multivariate analysis, T stage showed a significant correlation with improved OS and PFS. N stage showed a significant correlation with improved PFS. However, interval surgery-radiotherapy, reconstructive methods, and RT dose cannot serve as a significant prognostic factor for survival outcome.

Conclusion

This study suggests that treating no high-risk factors for locally advanced HPSCC with a dose of 50 Gy to the whole operative bed and elective lymph node levels cannot compromise disease control and survival.

Evaluating compliance with process-related quality metrics and survival in oral cavity squamous cell carcinoma: Multi-institutional oral cavity collaboration study

BACKGROUND

Process-related measures have been proposed as quality metrics in head and neck cancer care. A recent single-institution study identified four key metrics associated with increased survival. This study sought to validate the association of these quality metrics with survival in a multi-institutional cohort.

METHODS

Multicenter retrospective study of patients with oral cavity squamous cell (1/2005-1/2015). Baseline patient and disease characteristics and compliance with quality metrics was evaluated. Association between compliance with quality metrics with overall survival (OS), disease-free survival (DFS), and disease-specific survival (DSS) was evaluated using Cox proportional hazards models.

RESULTS

Failure to comply with two or more of the quality metrics was associated with worse OS, DFS, and DSS. Adherence to all or all but one of the quality metrics was found to be associated with improved survival.

CONCLUSIONS

Process-related quality metrics are associated with increased survival in patients with oral cavity squamous cell carcinoma in a multi-institutional cohort.

Pathology protocol increases lymph node yield in neck dissection for oral cavity squamous cell carcinoma

BACKGROUND

Lymph node yield (LNY) is a proposed quality indicator in neck dissection for oral cavity squamous cell carcinoma (OCSCC).

METHODS

Retrospective series including 190 patients with OCSCC undergoing neck dissection between 2016 and 2018. A change in pathologic grossing protocol was initiated during the study period to assess residual adipose tissue. A generalized linear model was used to assess the impact of multiple variables on LNY.

RESULTS

Mean LNY was 28.59 (SD = 17.65). The protocol identified a mean of 10.32 lymph nodes per case. Multivariable analysis identified associations between LNY and use of the pathology protocol (P = .02), number of dissected lymph node levels (P < .001), presence of pathologic lymph nodes (P = .002), body mass index (P = .02), prior neck surgery (P = .001), and prior neck radiation (P = .001).

CONCLUSIONS

Assessment of residual adipose tissue within neck dissection specimens improves accuracy of LNY. LNY in neck dissection is influenced by multiple factors including methods of pathologic assessment.

Framework for prioritizing head and neck surgery during the COVID-19 pandemic

The COVID-19 pandemic has placed an extraordinary demand on the United States health care system. Many institutions have canceled elective and non-urgent procedures to conserve resources and limit exposure. While operational definitions of elective and urgent categories exist, there is a degree of surgeon judgment in designation. In the present commentary, we provide a framework for prioritizing head and neck surgery during the pandemic. Unique considerations for the head and neck patient are examined including risk to the oncology patient, outcomes following delay in head and neck cancer therapy, and risk of transmission during otolaryngologic surgery. Our case prioritization criteria consist of four categories: urgent-proceed with surgery, less urgent-consider postpone > 30 days, less urgent-consider postpone 30 to 90 days, and case-by-case basis. Finally, we discuss our preoperative clinical pathway for transmission mitigation including defining low-risk and high-risk surgery for transmission and role of preoperative COVID-19 testing.

Association of Treatment Delays With Survival for Patients With Head and Neck Cancer: A Systematic Review

Importance

Delays in the delivery of care for head and neck cancer (HNC) are a key driver of poor oncologic outcomes and thus represent an important therapeutic target.

Objective

To synthesize information about the association between delays in the delivery of care for HNC and oncologic outcomes.

Evidence Review

A systematic review of the English-language literature in PubMed/MEDLINE and Scopus published between January 1, 2007, and February 28, 2018, was performed to identify articles addressing the association between treatment delays and oncologic outcomes for patients with HNC. Articles that were included (1) addressed cancer of the oral cavity, oropharynx, hypopharynx, or larynx; (2) discussed patients treated in 2004 or later; (3) analyzed time of diagnosis to treatment initiation (DTI), time from surgery to the initiation of postoperative radiotherapy, and/or treatment package time (TPT; the time from surgery through the completion of postoperative radiotherapy); (4) included a clear definition of treatment delay; and (5) analyzed the association between the treatment time interval and an oncologic outcome measure. Quality assessment was performed using the Institute of Health Economics Quality Appraisal Checklist for Case Series Studies.

Findings

A total of 18 studies met inclusion criteria and formed the basis of the systematic review. Nine studies used the National Cancer Database and 6 studies were single-institution retrospective reviews. Of the 13 studies assessing DTI, 9 found an association between longer DTI and poorer overall survival; proposed DTI delay thresholds ranged from more than 20 days to 120 days or more. Four of the 5 studies assessing time from surgery to the initiation of postoperative radiotherapy (and all 4 studies assessing guideline-adherent time to postoperative radiotherapy) found an association between a timely progression from surgery to the initiation of postoperative radiotherapy and improved overall or recurrence-free survival. Of the 5 studies examining TPT, 4 found that prolonged TPT correlated with poorer overall survival; proposed thresholds for prolonged TPT ranged from 77 days or more to more than 100 days.

Conclusions and Relevance

Timely care regarding initiation of treatment, postoperative radiotherapy, and TPT is associated with survival for patients with HNC, although significant heterogeneity exists for defining delayed DTI and TPT. Further research is required to standardize optimal time goals, identify barriers to timely care for each interval, and design interventions to minimize delays.

Best Practice in Surgical Treatment of Malignant Head and Neck Tumors

Purpose of review: Defining the best practice of surgical care for patients affected by malignant head and neck tumors is of great importance. In this review we aim to describe the evolution of “best practice” guidelines in the context of quality-of-care measures and discuss current evidence on “best practice” for the surgical treatment of cancers of the sino-nasal tract, skull base, aero-digestive tract, and the neck.

Recent findings: Current evidence based on certain structure and outcome indicators, but mostly based on process indicators already helps defining the framework of “Best practice” for head and neck cancer surgery. However, many aspects of surgical treatment still require in-depth research.

Summary: While a framework of “Best practice” strategies already exists for the conduction of the surgical treatment of head and neck cancers, many questions still require additional research in particular in case of rare histologies in the head and neck region.

Margins in Sinonasal Squamous Cell Carcinoma: Predictors, Outcomes, and the Endoscopic Approach

OBJECTIVES

To identify factors associated with positive margins following surgical management of sinonasal squamous cell carcinoma (SNSCC), especially with regard to endoscopic treatment.

METHODS

In a retrospective analysis of adult patients with clinically staged tumor (T)1 to T4a SNSCC within the National Cancer Database (NCDB) from 2004 to 2014, factors were associated with positive margins using multivariable binary logistic regression. Cases from 2010 to 2014 had surgical approach (open vs. endoscopic) available and were analyzed in a subgroup to assess the association of surgical approach with margin status. The association of margin status with overall survival (OS) and additional therapy administration was also assessed.

RESULTS

We identified 2,968 cases, of which 807 (27.2%) had positive margins. On multivariable analysis, factors associated with positive margins included higher T stage (T4a vs. T1: odds ratio [OR] 2.768 [95% CI 2.143-3.577]), less differentiated tumors (poorly differentiated vs. well differentiated: OR 1.403 [95% CI 1.060-1.856]), and tumors in the ethmoid sinus (vs. nasal cavity; OR 1.889 [95% CI 1.305-2.734]). Cases treated at higher volume facilities (HVFs) were associated with a lower likelihood of positive margins (OR 0.716 [95% CI 0.582-0.881]). Positive margins were associated with decreased OS (hazard ratio 1.672 [95% CI 1.464-1.908]) and an increased rate of additional therapy (OR 1.966 [95% confidence interval 1.597-2.421]). An endoscopic approach was not associated with an increased likelihood of obtaining positive margins (vs. open; OR 1.151 [0.903-1.651]).

CONCLUSION

Positive margins were less likely when performed at HVFs and more likely in the ethmoid sinus than other subsites. Importantly, there was no association between positive margins and surgical approach. Endoscopic surgery may offer a safe, less invasive alternative to open surgery for select patients.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:E388-E396, 2020.

Can Early Dental Extractions Reduce Delays in Postoperative Radiation for Patients With Advanced Oral Cavity Carcinoma?

PURPOSE

This study sought to evaluate the effect of early extractions on the timing of postoperative radiation (PORT) for patients with advanced oral cavity squamous cell carcinoma.

MATERIALS AND METHODS

All patients with oral cavity squamous cell carcinoma who required resection, free flap reconstruction, and dental extractions in a 10-year period were retrospectively reviewed. The study included patients who preoperatively had advanced disease that indicated the need for adjuvant radiation as defined by an advanced clinical T category (T3 or T4a) or clinical N category (N2a or above). Multivariate logistic regression models were created to estimate the risk factors for initiation of PORT greater than 6 weeks after surgery.

RESULTS

Thirty-four patients were included. Thirteen patients underwent early extractions (before or at the time of surgery). Twenty-one patients underwent extractions after surgery. Extractions included all teeth with periodontal disease within the expected field of radiation. Most patients underwent full-mouth extractions (91.1%). PORT was initiated at greater than 6 weeks in 30.8% of patients in the early cohort, whereas 72.4% of patients in the late group experienced a delay (P = .02). Early extractions were significantly associated with a decreased risk of PORT delay. No increase in operating room time occurred for patients who underwent same-day extractions.

CONCLUSIONS

Early involvement of the dental oncology department and oral-maxillofacial surgeons can aid in the timely delivery of care for patients with advanced oral cavity cancer.

Quality assurance in head and neck cancer surgery: where are we, and where are we going?

PURPOSE OF REVIEW

The scope of this review is to summarize current efforts in quality assurance for head and neck cancer surgery. National and international initiatives are summarized and progress in terms of identification of process indicators and outcome indicators delineated.

RECENT FINDINGS

Massive efforts have been made in order to improve quality of head and neck cancer surgery. New guidelines for quality assurance of head and neck cancer surgery in clinical trials have recently been proposed by EORTC.

SUMMARY

Quality assurance programs can be tested within the clearly defined environment of prospective clinical trials. If positive, such programs could be rolled out within national healthcare systems, if feasible. Testing quality programs in clinical trials could be a versatile tool to help head neck cancer patients benefit from such initiatives on a global level.

Analysis of Process-Related Quality Metrics and Survival of Patients with Oral Cavity Squamous Cell Carcinoma

Objective

To analyze the association of prior reported key quality metrics—neck dissection ≥18 nodes, radiation oncology referral for stage III/IV disease, unplanned surgery ≤14 days, and unplanned readmission ≤30 days—with disease-free survival (DFS) and overall survival (OS) in oral cavity cancer (OCC).

Study Design

A retrospective chart review.

Setting

A tertiary care center from 1995 to 2016.

Subjects and Methods

Data from patients with OCC who underwent primary surgery were studied. The association of quality metrics and pathology with DFS/OS was determined by Cox proportional hazards regression analysis.

Results

A total of 514 patients were included, and 398 (77.4%) underwent elective neck dissection. Key metrics were not associated with DFS on analysis, but higher pathologic stage and extracapsular extension (ECE) were. When stratified by stage, unplanned readmission within 30 days was associated with decreased survival on multivariate analysis (HR = 0.40; 95% CI, 0.20-0.85; P = .02) for patients with clinical stage III or IV disease. ECE was associated with decreased survival among these patients as well. Neck dissection with ≤18 nodes (HR = 0.62; 95% CI, 0.44-0.86; P = .004) and unplanned surgery within 14 days (HR = 0.56; 95% CI, 0.32-0.96; P = .03) were associated with decreased survival on univariate analysis but not on multivariate analysis. ECE and higher-stage disease were associated with decreased OS on multivariate analysis.

Conclusion

In this study, aggressive pathology, rather than adherence to key quality metrics, was associated with lower DFS and OS among patients with OCC. More studies are needed to elucidate the association of quality metrics with survival.

Association of Care Processes With Timely, Equitable Postoperative Radiotherapy in Patients With Surgically Treated Head and Neck Squamous Cell Carcinoma

Importance

Delays in initiation of postoperative radiotherapy (PORT) after surgery for head and neck squamous cell carcinoma (HNSCC) are common, predominantly affect racial minorities, and are associated with decreased survival. Details regarding the care processes that contribute to timely, equitable PORT remain unknown.

Objective

To determine care processes associated with timely, equitable PORT.

Design, Setting, and Participants

This retrospective cohort study included patients 18 years or older undergoing surgery for HNSCC at the Medical University of South Carolina (MUSC), Charleston, followed by PORT (at MUSC or elsewhere) with or without chemotherapy from January 1, 2014, through December 31, 2016. Data were analyzed from September 15, 2017, through June 28, 2018.

Main Outcomes and Measures

The main outcome measure was the proportion of timely, guideline-adherent initiation of PORT (≤6 weeks postoperatively). Secondary outcome measures included care processes associated with timely PORT. The association between process variables with timely PORT was explored using multivariable logistic regression analysis. Effect modification of the association between receipt of care processes and timely PORT by race was explored using interaction effects.

Results

A total of 197 patients were included in the analysis; they were predominantly white (157 [79.7%]) and male (136 [69.0%]) with a mean age of 59 years (range, 28-89 years). Overall, 89 patients (45.2%) experienced a delay initiating PORT. African American patients had a 13.5% absolute increase in the rate of delayed PORT relative to white patients (21 of 37 [56.8%] vs 68 of 157 [43.3%]). The adjusted multivariable regression showed that the following care processes were associated with timely PORT: preoperative radiotherapy consultation (odds ratio [OR], 8.94; 95% CI, 1.64-65.53), PORT at MUSC (OR, 6.21; 95% CI, 1.85-24.75), pathology report within 7 postoperative days (OR, 4.14; 95% CI, 1.21-15.86), time from surgery to PORT referral of no longer than 10 days (OR, 12.14; 95% CI, 3.14-63.00), time from PORT referral to consultation of no longer than 10 days (OR, 10.76; 95% CI, 3.01-49.70), and time from PORT consultation to its start of no longer than 21 days (OR, 4.80; 95% CI 1.41-18.44). Analysis of interactions revealed no statistically significant differences between African American and white patients in receipt of key processes associated with timely PORT.

Conclusions and Relevance

Specific care processes are associated with guideline-adherent initiation of PORT. Novel strategies appear to be needed to ensure that these processes are performed for all patients with HNSCC, thereby facilitating timely, equitable PORT.

Evaluation of early oral cavity cancer treatment quality at a single institution

OBJECTIVE

To evaluate the adherence to oral cavity quality guidelines endorsed by the American Head and Neck Society (AHNS) at a large tertiary care hospital.

METHODS

This retrospective study identified patients treated for early-stage oral tongue squamous cell carcinoma at a tertiary care hospital from 1992 to 2013. Patient charts were reviewed for 26 process quality measures and four key indicator process quality measures as endorsed by the AHNS. Patients were then grouped by diagnosis date either before (historical group, 1992-2007) or after (current treatment group, 2008-2013) the published process quality measures from the AHNS. Descriptive statistics were used to evaluate the rates of adherence for each process quality measure within the 2 groups.

RESULTS

Of the 57 patients identified, 29 were female (51%). The mean age was 62.3 years. A majority of the oral cavity cancers were stage I (59.6%), followed by stage II (35.1%) and stage III (5.3%). Compliance with the process quality measures was in the acceptable range in both cohorts. However, several areas demonstrated lower adherence in both cohorts. Statistically significant improvements were noted between the two cohorts, which showed a measurable improvement in adherence to process quality measures in several key areas over time.

CONCLUSION

Using the process quality measures proposed by the AHNS, adherence to the process quality measures for early-stage oral cavity cancer care at a tertiary care center was successfully evaluated. In general, good compliance with the proposed process quality measures was found and several areas for improvement were identified.

LEVEL OF EVIDENCE

2c Laryngoscope, 129:1816-1821, 2019.

Treatment Patterns in Veterans with Laryngeal and Oropharyngeal Cancer and Impact on Survival

Objectives

Veterans with laryngeal and oropharyngeal cancer remain an understudied patient population despite a high incidence of disease and decreased survival compared to the general population. Our objective was to evaluate treatment patterns for laryngeal and oropharyngeal cancer in patients treated at one of the Veterans Health Administration's busiest cancer centers in order to generate some basic benchmarks for treatment delivery in the veteran population.

Methods

We reviewed 338 patients treated at the Michael E. DeBakey Veterans Affairs Medical Center between 2000 and 2012.

Results

Oropharyngeal site and advanced age were associated with worse overall and disease‐free survival. Treatment periods (mean) were as follows: 1) referral‐diagnosis, 26 days; 2) diagnosis‐surgery, 29 days; and 3) diagnosis‐radiation, 58 days. Adjuvant radiation was initiated within 6 weeks of surgery in 42% of patients and 68% of patients had a total treatment package time ≤100 days. Time from diagnosis to treatment initiation, surgery to adjuvant radiation interval and total treatment package time did not impact survival.

Conclusions

This study establishes basic benchmarks for laryngeal and oropharyngeal cancer treatment delivery in veterans. Additional efforts are warranted to improve consistency and provide treatment in line with NCCN recommendations and literature consensus.

Level of Evidence

2b

Treatment Times in Salivary Gland Cancer: National Patterns and Association with Survival

Objective To characterize treatment times in salivary cancer; associate treatment times with patient, tumor, and treatment characteristics; and examine the association of treatment times and overall survival. Study Design Retrospective cohort. Setting Commission-on-Cancer Accredited Hospitals 2004-2013. Subjects and Methods In total, 5953 patients with salivary cancer included in the National Cancer Database were identified. For each treatment interval, patients in the fourth quartile ("prolonged") were compared to patients in the first and second quartiles ("not prolonged"). Patient, tumor, and treatment characteristics were associated with prolonged times via multivariable binary logistic regression. Prolongation of each interval was associated with overall survival via multivariable Cox proportional hazards regression, controlling for clinically relevant factors. Results Median durations for diagnosis-to-treatment initiation, surgery-to-radiation treatment (RT), RT duration, total treatment package, and diagnosis-to-treatment end were 31, 44, 47, 92, and 110 days, respectively. Race, insurance status, comorbidities, age, T and N stage, facility volume and location, and a facility care transition from diagnosis to initial treatment were associated with prolonged treatment time. Prolonged RT duration was associated with decreased overall survival (OS) (62% vs 75% 5-year OS, HR = 1.26 [95% confidence interval (CI), 1.09-1.47]; P = .002), but prolonged diagnosis-to-treatment initiation, surgery-to-RT, total treatment package, and diagnosis-to-treatment end intervals were not (70% vs 67% 5-year OS, HR = 1.11 [95% CI, 0.92-1.34], P = .284; 72% vs 68%, HR = 0.93 [95% CI, 0.79-1.09], P = .370; 70% vs 70%, HR = 1.00 [95% CI, 0.84-1.20], P = .974; 66% vs 71%, HR = 0.99 [95% CI, 0.84-1.18], P = .920, respectively). Conclusion The median durations identified here can serve as reference points. Radiation therapy duration is associated with overall survival in salivary cancer and could be considered a quality indicator.

Performance Improvement in Head and Neck Cancer

Performance improvement requires establishing a platform to set benchmarks and monitor the quality of care provided through quality indicators and metrics. This has long been recognized as critical to overall quality improvement and more recently, has become federally mandated. Here, we review recent studies evaluating performance in head and neck cancer care, from those spanning all phases of head and neck cancer care to others focused on head and neck surgical performance, including both national and departmental/institutional efforts.

Measuring Institutional Quality in Head and Neck Surgery Using Hospital-Level Data: Negative Margin Rates and Neck Dissection Yield

Importance

Negative margins and lymph node yields (LNY) of 18 or more from neck dissections in patients with head and neck squamous cell carcinomas (HNSCC) have been associated with improved patient survival. It is unclear whether these metrics can be used to identify hospitals with improved outcomes.

Objective

To determine whether 2 patient-level metrics would predict outcomes at the hospital level.

Design, Setting, and Participants

A retrospective review of records from the National Cancer Database (NCDB) was used to identify patients who underwent primary surgery and concurrent neck dissection for HNSCC between 2004 and 2013. The percentage of patients at each hospital with negative margins on primary resection and an LNY 18 or more from a neck dissection was quantified. Cox proportional hazard models were used to define the association between hospital performance on these metrics and overall survival.

Main Outcomes and Measures

Margin status and lymph node yield at hospital level. Overall survival (OS).

Results

We identified 1008 hospitals in the NCDB where 64 738 patients met inclusion criteria. Of the 64 738 participants, 45 170 (69.8%) were men and 19 568 (30.2%) were women. The mean SD age of included patients was 60.5 (12.0) years. Patients treated at hospitals attaining the combined metric of a 90% or higher negative margin rate and 80% or more of cases with LNYs of 18 or more experienced a significant reduction in mortality (hazard ratio [HR] 0.93; 95% CI, 0.89-0.98). This benefit in survival was independent of the patient-level improvement associated with negative margins (HR, 0.73; 95% CI, 0.71-0.76) and LNY of 18 or more (HR, 0.85; 95% CI, 0.83-0.88). Including these metrics in the model neutralized the association of traditional measures of hospital quality (volume and teaching status).

Conclusions and Relevance

Treatment at hospitals that attain a high rate of negative margins and LNY of 18 or more is associated with improved survival in patients undergoing surgery for HNSCC. These surgical outcome measures predicted outcomes independent of traditional, but generally nonmodifiable characteristics. Tracking of these metrics may help identify high-quality centers and provide guidance for institution-level quality improvement.

Effect of time to initiation of postoperative radiation therapy on survival in surgically managed head and neck cancer

BACKGROUND

The objective of this study was to determine the effects of National Comprehensive Cancer Network (NCCN) guideline-adherent initiation of postoperative radiation therapy (PORT) and different time-to-PORT intervals on the overall survival (OS) of patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

The National Cancer Data Base was reviewed for the period of 2006-2014, and patients with HNSCC undergoing surgery and PORT were identified. Kaplan-Meier survival estimates, Cox regression analysis, and propensity score matching were used to determine the effects of initiating PORT within 6 weeks of surgery and different time-to-PORT intervals on survival.

RESULTS

This study included 41,291 patients. After adjustments for covariates, starting PORT >6 weeks postoperatively was associated with decreased OS (adjusted hazard ratio [aHR], 1.13; 99% confidence interval [CI], 1.08-1.19). This finding remained in the propensity score-matched subset (hazard ratio, 1.21; 99% CI, 1.15-1.28). In comparison with starting PORT 5 to 6 weeks postoperatively, initiating PORT earlier was not associated with improved survival (aHR for ≤ 4 weeks, 0.93; 99% CI, 0.85-1.02; aHR for 4-5 weeks, 0.92; 99% CI, 0.84-1.01). Increasing durations of delay beyond 7 weeks were associated with small, progressive survival decrements (aHR, 1.09, 1.10, and 1.12 for 7-8, 8-10, and >10 weeks, respectively).

CONCLUSIONS

Nonadherence to NCCN guidelines for initiating PORT within 6 weeks of surgery was associated with decreased survival. There was no survival benefit to initiating PORT earlier within the recommended 6-week timeframe. Increasing durations of delay beyond 7 weeks were associated with small, progressive survival decrements. Cancer 2017;123:4841-50. © 2017 American Cancer Society.

Evaluation of Quality Metrics for Surgically Treated Laryngeal Squamous Cell Carcinoma

Importance

Quality metrics for patients with laryngeal squamous cell carcinoma (SCC) exist, but whether compliance with these metrics correlates with improved survival is unknown.

Objective

To examine whether compliance with proposed quality metrics is associated with improved survival in patients with laryngeal SCC treated with surgery with or without adjuvant therapy.

Design, Setting, and Participants

This retrospective cohort study included patients from a tertiary care academic medical center who had previously untreated laryngeal SCC and underwent surgery with or without adjuvant therapy from January 1, 2003, through December 31, 2012. Data analysis was performed from August 4, 2015, through December 13, 2015.

Interventions

Surgery with or without adjuvant therapy.

Main Outcomes and Measures

Compliance with quality metrics from the American Head and Neck Society (AHNS), National Comprehensive Cancer Network (NCCN) guidelines, and institutional metrics with face validity covering pretreatment evaluation, treatment, and posttreatment surveillance was evaluated. The association between compliance with the group of metrics and overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS) was explored using Cox proportional hazards analysis. The association between compliance with individual metrics and survival was similarly determined.

Results

A total of 243 patients (184 men and 59 women) were included in the study (median age, 62 years; age range, 23-87 years). No association was found between increasing levels of compliance with the AHNS or NCCN metrics and survival. The only AHNS or NCCN metric for which greater compliance correlated with improved survival on multivariable Cox proportional hazards analysis controlling for pT stage, pN stage, extracapsular spread, margin status, and comorbidity was pretreatment multidisciplinary evaluation for patients with stage cT3-4 or cN1-3 disease (OS adjusted hazard ratio [aHR], 0.47; 95% CI, 0.24-0.94; DFS aHR, 0.45; 95% CI, 0.23-0.85). For the institutional metrics, multidisciplinary evaluation for all patients (OS aHR, 0.51; 95% CI, 0.29-0.88; DFS aHR, 0.50, 95% CI, 0.32-0.80) and elective neck dissection yield of 18 lymph nodes or more (DFS aHR, 0.36; 95% CI, 0.14-0.99) were associated with improved survival on multivariable Cox proportional hazards analysis.

Conclusions and Relevance

In this cohort of patients with surgically treated laryngeal SCC, multidisciplinary evaluation and elective neck dissection yield of 18 lymph nodes or more are associated with improved survival. Development of better quality metrics is necessary because increased compliance with metrics described by the AHNS and NCCN is not associated with improved survival. Previously described metrics for surgically treated oral cavity cancer are not prognostic for surgically treated laryngeal SCC. Future multi-institutional collaboration will be required to validate these findings, develop better quality metrics, and evaluate whether quality metrics for head and neck cancer are site specific.

Lymph Node Count From Neck Dissection Predicts Mortality in Head and Neck Cancer

Purpose

Multiple smaller studies have demonstrated an association between overall survival and lymph node (LN) count from neck dissection in patients with head and neck cancer. This is a large cohort study to examine these associations by using a national cancer database.

Patients and Methods

The National Cancer Database was used to identify patients who underwent upfront nodal dissection for mucosal head and neck squamous cell carcinoma between 2004 and 2013. Patients were stratified by LN count into those with < 18 nodes and those with ≥ 18 nodes on the basis of prior work. A multivariable Cox proportional hazards regression model was constructed to predict hazard of mortality. Stratified models predicted hazard of mortality both for patients who were both node negative and node positive.

Results

There were 45,113 patients with ≥ 18 LNs and 18,865 patients with < 18 LNs examined. The < 18 LN group, compared with the ≥ 18 LN group, had more favorable tumor characteristics, with a lower proportion of T3 and T4 lesions (27.9% v 39.8%), fewer patients with positive nodes (46.6% v 60.5%), and lower rates of extracapsular extension (9.3% v 15.1%). Risk-adjusted Cox models predicting hazard of mortality by LN count showed an 18% increased hazard of death for patients with < 18 nodes examined (hazard ratio [HR] 1.18; 95% CI, 1.13 to 1.22). When stratified by clinical nodal stage, there was an increased hazard of death in both groups (node negative: HR, 1.24; 95% CI, 1.17 to 1.32; node positive: HR, 1.12; 95% CI, 1.05 to 1.19).

Conclusion

The results of our study demonstrate a significant overall survival advantage in both patients who are clinically node negative and node positive when ≥ 18 LNs are examined after neck dissection, which suggests that LN count is a potential quality metric for neck dissection.