Missed Adjuvant Therapy in Human Papillomavirus Positive Oropharyngeal Squamous Cell Carcinoma

Objective Investigate missed adjuvant therapy and associated disparities in overall survival (OS) for human papillomavirus-associated (HPV+) oropharyngeal squamous cell carcinoma (OPSCC). Methods The 2010-2017 National Cancer Database was queried for patients with surgically resected HPV+ OPSCC. Indications for adjuvant radiotherapy (aRT) included pT3-4 classification, pN2-3 classification, lymphovascular invasion, pathologic extranodal extension (pENE), and/or positive surgical margins (PSM). Indication(s) for adjuvant chemoradiotherapy (aCRT) included pENE and/or PSM. Multivariable logistic and Cox regression models were implemented. Results Of 5297 patients satisfying inclusion criteria, 4288 had indication(s) for aRT; 775 did not receive any adjuvant therapy and were considered as missing aRT. A total of 2234 patients had indication(s) for aCRT. Of these, 1383 (61.9%) received aCRT, 555 (24.8%) patients received aRT alone and were considered as having missed aCRT, and 296 (13.2%) did not receive any adjuvant therapy. Missed aRT and missed aCRT were each associated with age, treatment facility type, pN classification, and surgical margin status (p < 0.015). Among patients with indication(s) for aRT alone, OS of those receiving no adjuvant therapy, aRT alone, and aCRT was 90.0%, 94.8%, and 93.4%, respectively (p = 0.080). Among patients with indication(s) for aCRT, those receiving aRT alone and aCRT had similar OS (89.0% vs. 86.6%, p = 0.357) which was superior to receiving no adjuvant therapy (74.9%, p < 0.001). These patterns in OS persisted on multivariable Cox regression. Conclusion Among patients with HPV+ OPSCC and indication(s) for aRT, missed aRT was not associated with worse OS. For patients with indication(s) for aCRT, aRT alone was associated with similar OS as aCRT.