Postoperative radiotherapy dose requirement in standard combined-modality practice for head and neck squamous cell carcinoma: Analysis of salient surgical and radiotherapy parameters in 2 cohorts.

Background: This study compared 2 sequential cohorts to identify the postoperative radiotherapy (PORT) dose requirement for head and neck squamous cell carcinoma (HNSCC).

Methods: Two distinct PORT dose regimens were prescribed over 11 years; group 1 received 56 Gy or less, and group 2 received 60 Gy or more. The 2D and 3D techniques were used.

Results: Two sequential cohorts consisted of 478 patients, with mean and median follow-up for group 1 and 2 as: 37.0 versus 28.5 months and 13.8 versus 13.1 months, respectively. Grades 3-4 mucosal toxicities (11.4% vs 28.3%), hospitalization (3.2% vs 17.4%), and nasogastric feeding (11.9% vs 29.7%) were higher in group 2. The 2-year disease-free survival (DFS) was higher with PORT >60 Gy for the following factors: age ≤ 50 years (P = .041); ≥ 4 positive nodes (P = .029); and overall treatment time (OTT) ≥ 100 days (P = .042).

Conclusion: Except for the benefit of doses >60 Gy for limited parameters, a lower PORT dose did not compromise the results and can potentially reduce the morbidities and healthcare costs.