Highly conformal reirradiation in patients with prior oropharyngeal radiation: Clinical efficacy and toxicity outcomes.

Background: Reirradiation of head and neck cancer is associated with high rates of locoregional failure and potentially severe treatment-related toxicity. We report our institutional experience of reirradiation using modern highly conformal radiotherapy approaches in patients with prior oropharyngeal radiation.

Methods: We reviewed patients receiving curative-intent reirradiation with intensity-modulated radiation therapy, stereotactic body radiation therapy, and proton beam radiotherapy at our institution from 1999 to 2019. Disease control, survival, and toxicity rates following reirradiation were determined.

Results: Sixty-nine patients were evaluated. Local control (LC), progression-free survival, and overall survival at 2 years following reirradiation were 77%, 35%, and 51%, respectively. Grade 3 or greater (G3+) late toxicities occurred in 46% of patients and 41% required feeding tube placement during or after reirradiation.

Conclusions: In select patients with prior oropharyngeal radiation, highly conformal reirradiation offers acceptable LC, but G3+ toxicity and out-of-field failure rates remain high. These findings warrant continued evaluation of new multimodality approaches to improve oncologic outcomes.