Institution-level Patterns of Care for Early-stage Oropharynx Cancers in the United States.

Objectives: The adoption of transoral robotic surgery and shifting epidemiology in oropharyngeal squamous cell cancer have stimulated debate over upfront and adjuvant treatment. Institutional variation in practice patterns can be obscured in patient-level analyses. We aimed to characterize institutional patterns of care as well as identify potential associations between patterns of care and survival.

Methods: This was a retrospective cohort study of patients identified from 2004-2015 in the National Cancer Database. We analyzed 42,803 cases of oropharyngeal squamous cell cancer Stage cT1-2N0-2bM0 (AJCC 7th edition) treated with curative intent surgery and/or radiotherapy. We defined facility-4-year periods to account for changing institutional practice patterns. The 42,803 patients were treated within 2578 facility-4-year periods. We assessed institutional practice patterns, including the ratio of upfront surgery to definitive radiotherapy, case volumes, use of adjuvant therapies (radiotherapy or chemoradiotherapy), and margin positivity rates. Survival associations with institutional practice patterns were estimated with Cox regression.

Results: The ratio of upfront surgery to definitive radiotherapy ranged from 80-to-1 to 1-to-23. The institution-level median rate of adjuvant radiotherapy was 69% (IQR 50%-100%), adjuvant chemoradiotherapy was 44% (IQR 0%-67%), and margin-positive resection was 33% (IQR 0%-50%). On patient-level MVA, worse overall survival was not significantly associated with institutional case volume, adjuvant radiotherapy, or adjuvant chemoradiotherapy utilization.

Conclusions: High rates of multimodal therapy and positive margins underscore the importance of multidisciplinary care and highlight variable patterns of care across institutions. Further work is warranted to explore indicators of high-quality care and to optimize adjuvant therapy in the HPV era.