Impact of chemotherapy regimen on treatment outcomes in patients with HPV-associated oropharyngeal cancer with T4 disease treated with definitive concurrent chemoradiation

Objectives Although human papilloma virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is typically associated with a good prognosis, patients with T4 disease experience relatively high rates of treatment failure. Our aim was to identify predictors of relapse among patients with clinical T4 disease. Material & Methods A retrospective review was conducted of 93 consecutive patients who underwent definitive concurrent chemoradiation for HPV-associated OPSCC with clinical T4 disease from July 2006 to December 2015. Three-year outcomes, including locoregional recurrence (LRR), distant metastasis (DM), overall survival (OS), and cancer-specific survival (CSS), were examined and reported from the date of treatment completion. Multivariable analysis using a Cox proportional hazards model was performed to test associations between outcome and patient and disease characteristics as well as chemotherapy regimen (high-dose cisplatin (HDC) vs. other). Results Median follow-up for surviving patients was 50 months (range 18–133). For all-comers, 3-year rates of LRR, DM, OS, and CSS were 15%, 19%, 79%, and 86%, respectively. On multivariable analysis, the only factor prognostic for patient outcomes was the chemotherapy regimen. For patients who received HDC vs. an alternative regimen, 3-year LRR, DM, OS, and CSS, were 9% vs. 20% (p = 0.09), 10% vs. 28% (p = 0.04), 89% vs. 67% (p = 0.04), and 96% vs. 77% (p = 0.02), respectively. Conclusion In patients with HPV-associated OPSCC bearing clinical T4 disease, receipt of a concurrent systemic agent other than HDC resulted in increased treatment failure and inferior survival. This analysis suggests that HDC should remain the preferred concurrent regimen for these patients.