Post-Operative Concurrent Chemoradiation for Patients with Non-Squamous Cell Carcinoma of Head and Neck: A Retrospective Cohort of the Uncommon Cancers

: Background: Non-squamous cell carcinoma of the head and neck (HNnSCCA) is a rare tumor. Surgery is the standard treatment for resectable non-metastatic patients. Post-operative radiation (RT) is indicated for high-risk patients. No data from the randomized controlled trial utilizing post-operative concurrent chemoradiation (CCRT) is available. This study was aimed to determine the benefit of post-operative CCRT in the patients with resectable non-metastatic HNnSCCA. Methods: We retrospectively reviewed data of 139 patients with HNnSCCA (excluding nasopharyngeal, neuroendocrine, and skin cancers) who underwent surgery and post-operative radiation (RT) at Siriraj Hospital from 2009–2015. Results: Ninety-nine of the 139 patients had RT alone and 40 had CCRT. More patients receiving CCRT had ≥ one high-risk feature (80% CCRT vs. 57.6% RT; p=0.018). Five-year disease-free survival (DFS) and overall survival (OS) did not differ between the groups (58.6% CCRT vs. 68.2% RT; p=0.35 and 81.7% CCRT vs. 81.0% RT; p=0.35, respectively). Interestingly, post-operative CCRT was independently associated with significantly superior DFS (hazard ratio, HR 0.29; 95% confidence interval, CI 0.10 to 0.86; p=0.02) and OS (HR 0.08; 95% CI 0.01 to 0.43; p=0.003) according to multivariable analyses. Conclusion: Post-operative CCRT was associated with better survival in high-risk patients with resectable non-metastatic HNnSCCA comparing with post-operative RT alone. Post-operative CCRT might be considered as a treatment option for these patients.