Fifteen Years of Experience With Stereotactic Body Radiation Therapy for Recurrent Head and Neck Cancers: A Detailed Analysis of Patients With Carotid Blowout Syndrome.

Abstract

To evaluate the treatment outcomes and toxicity profile of stereotactic body radiation therapy (SBRT) for second-course radiation therapy (RT) in patients with recurrent head and neck cancer. Data from 191 patients treated with SBRT between September 2007 and February 2022 were retrospectively reviewed. Patients were stratified based on Multi-Institution Reirradiation Collaborative recursive partitioning analysis (RPA) score. Kaplan-Meier survival analyses were performed to assess overall survival (OS), progression-free survival (PFS), and locoregional recurrence-free survival (LRRFS). Univariate and multivariate logistic regression analyses were performed to identify factors predicting carotid blowout syndrome (CBOS), with receiver operating characteristic curve analysis to determine significant cutoff values. The median follow-up was 13 months (range, 1-178.69 months) for the entire cohort and 19 months (range, 1-178 months) for surviving patients. Two-year OS was 39%, with a median survival of 15.2 months. The 2-year PFS was 21%, with a median PFS of 9.5 months. Significant predictors of OS included the interval between RT courses (P = .01) and gross tumor volume (P = .02). Primary tumor location (nasopharynx vs other primary locations) and the interval between RT courses were predictive of both PFS and LRRFS (P = .01, P = .04, and P = .04, P = .01, respectively). Gross tumor volume was prognostic for LRRFS (P = .02). Multi-Institution Reirradiation Collaborative RPA classification was not a prognostic factor. Late ≥grade 3 toxicity occurred in 43 patients (22.5%), with 26 patients (13.6%) experiencing CBOS. Age and carotid artery entrapment ≥180° were identified as predictors for CBOS. Receiver operating characteristic curve analysis established an optimal age cutoff of 51 years for predicting CBOS, with 73% sensitivity and 72% specificity. Reirradiation with SBRT is feasible for treating recurrent head and neck cancer. Patient selection is critical for identifying suitable candidates for SBRT, and a distinct RPA score may be required for these patients. Prophylactic measures and close follow-up are essential for high-risk patients to prevent CBOS.