Examining adjuvant radiation dose in head and neck squamous cell carcinoma

Background: Compare adjuvant radiation dose trends and outcomes in head and neck squamous cell carcinoma (HNSCC). Methods: Nonmetastatic HNSCCs treated between 2004 and 2014 with primary site surgery, lymph node dissection, and adjuvant radiation were identified in the National Cancer Database. Standard dose radiation (SD-RT) was defined as an equivalent dose in 2 Gy (EQD2) ≥56.64 and ≤60 Gy and high-dose radiation (HD-RT) as an EQD2 >60 and <70 Gy. Results: HD-RT was given to 46% of the 15 836 HNSCC patients managed with adjuvant radiation. When adjusted for poor prognostic factors, HD-RT was associated with increased mortality (HR1.09; 95%CI 1.02-1.16). In nonoropharynx or human papillomavirus-negative oropharynx primary that had positive margins, ≥5 positive lymph nodes, and/or extranodal extension, HD-RT was still not associated with improved survival (HR 1.01, 95% CI 0.91-1.12). Conclusions: There was no survival benefit from postoperative dose escalation above EQD2 60 Gy even in a high-risk cohort.