E. Laseinde1, L. Guan1, R. Hildebrand2, N. Meurice1, M. F. Gensheimer1, B. M. Beadle1, F. C. Holsinger3, J. Sunwoo3, F. M. Baik3, D. Sirjani3, V. Divi3, M. J. Kaplan4, H. Pinto2, A. D. Colevas2, M. Rahman5, and Q. T. Le1; 1Radiation Oncology, Stanford University, Stanford, CA, 2Medicine - Med/Oncology, Stanford University, Stanford, CA, 3Otolaryngology - Head and Neck Surgery, Stanford University, Stanford, CA, 4Otolaryngology - Head and Neck Surgery, Stanford University, Emeritus, Stanford, CA, 5Pathology, Stanford University, Stanford, CA
Purpose/Objective(s): Radiation induced cancers (RICs) are rare; however, the prognosis is poor. Here, we evaluate the survival rate of patients with RICs from a prior head and neck cancer (pHNC) treatment in those with resectable versus unresectable RICs. Materials/
Methods: We defined RICs as those arising within the irradiated field more than five years from the radiation treatment (RT) for their pHNC. We performed an IRB-approved retrospective review to identify these patients and collect patient and treatment characteristics. Overall survival was defined from the date of RIC diagnosis and computed using Kaplan-Meier survival curves. Log-rank test was used to compare survival rates for the different treatment groups. Results: Between 2006 and 2023, 50 patients with a diagnosis of RIC from pHNC were seen at our institution. The median age at diagnosis of RIC was 69 years old (range 38-83) and the median time of RIC presentation from the prior RT was 12.5 years (range 4-57). 72% were male, 94% were not Hispanic or Latino, and 76% were White. 86% of RICs were of squamous histology. The most common sites of pHNC were oropharynx (OP: 44%), nasopharynx (NP: 20%), and oral cavity (OC: 18%). The most common sites of RICs were OC (40%), OP (24%), hypopharynx (6%) and paranasal sinus (6%). 26 (52%) of patients received surgery +/- postop RT +/- chemotherapy, 18 (36%) received non-surgical treatment with 12 (24%) receiving immunotherapy as part of the regimen, and 6 (12%) receiving no therapy. At a median follow up of 1.4 years (range: 0.4-13.3) for live and treated patients (n=28), the two-year estimated survival was 85% for the surgical vs 34% for the nonsurgical group (p=0.0004). For the nonsurgical group, the only survivors past one year were those who received immunotherapy as part of their treatment (n=12). Conclusion: Consistent with prior literature, patients that received surgery for their RICs had better survival than those treated with non-surgical therapy. Interestingly, patients who received immunotherapy in the non-surgical group had longer survival than those without, although the numbers were too small to draw a definitive conclusion.
