Outcomes following radiation for cutaneous squamous cell carcinoma of the head and neck: Associations between immune suppression and recurrence

Background: Data evaluating outcomes and patterns of recurrence following radiation therapy (RT) for cutaneous squamous cell carcinoma (cSCC) of the head and neck are limited. Methods: We performed a retrospective analysis of 111 head and neck cSCC patients treated with RT at 4 affiliated institutions. Results: With median follow-up of 7 months, there were 29 (26%) recurrences, 73% of which were nodal (n = 21). Immunosuppression (IS) was the only factor associated with recurrence (47% in IS, 22% in non-IS, P =.04), and also with time to recurrence in multivariate analysis (HR 5.5; P =.03). No factors were associated with recurrence among patients who received definitive RT. The majority of patients who recurred were salvaged with surgery (n = 20, 69%). Conclusion: In a cohort of cSCC treated with radiotherapy, there was an association between IS and increased failure risk. The majority of failures were salvaged surgically.