Reirradiation for second primary or recurrent cancers of the head and neck: Dosimetric and outcome analysis

Background. The purpose of this study was to examine outcomes, toxicity, and dosimetric characteristics of patients treated with reirradiation for head and neck cancers. Methods. Fifty patients underwent >= 2 courses of radiation therapy (RT) postoperatively or definitively with or without chemotherapy. Composite dose volume histograms (DVHs) for selected anatomic structures were correlated with grade >= 3 late toxicity. Results. Median initial and retreatment radiation dose was 64 and 60 Gy, respectively. Median overall survival (OS), progression-free survival (PFS), and 1-year PFS rates were 18 months, 11 months, and 45%, respectively, with 13 months median follow-up. Thirty-four percent of patients experienced grade >= 3 late toxicity with 1 death from carotid blowout. The DVH corresponding to the carotid blowout fell above the third quartile compared with other patients. Conclusion. Our analysis is the first to systematically evaluate the dose to the carotid artery using composite dosimetry in head and neck reirradiation patients, and demonstrates a promising technique for evaluating the dose to other normal tissue structures. (c) 2015 Wiley Periodicals, Inc.