Comparing adjuvant radiation to adjuvant chemoradiation in postsurgical p16+ oropharyngeal carcinoma patients with extranodal extension or positive margins.

Background: Adjuvant guidelines in surgically resected p16+ oropharyngeal carcinoma (OPC) with positive surgical margins (PSM) or extranodal extension (ENE) are based on randomized controlled trials predating p16 status. It remains unclear if adjuvant chemotherapy is necessary in p16+ patients with these features. Methods: The National Cancer Database was used to identify cases of nonmetastatic p16+ OPC diagnosed from 2010 to 2017. Patients treated with surgical resection followed by adjuvant radiation (aRT) or adjuvant chemoradiation (aCRT) were eligible for analysis. Results: A total of 14 071 patients were eligible for analysis. Overall survival (OS) was not statistically different between aRT and aCRT in patients with PSM (hazard ratio (HR) 0.84, 95% confidence interval (CI) 0.56–1.28), ENE (HR 0.93, 95% CI 0.69–1.27) or both (HR 0.73, 95% CI 0.41–1.31). Conclusions: In patients with p16+ OPC with ENE, PSM, or both, adding chemotherapy to aRT was not associated with improved OS. [ABSTRACT FROM AUTHOR]