Mucosal Sparing Radiation Therapy in Resected Oropharyngeal Cancer

Purpose: To report the outcomes of patients with favorable risk oropharyngeal cancer that underwent adjuvant radiation therapy with omission of the primary site from the clinical target volume (CTV). Material/ Methods: A retrospective study of 40 patients treated with transoral surgery (TOS) followed by neck only radiation using intensity modulated radiation therapy (IMRT) with exclusion of the primary site. For all patients, a CTV of the primary surgical bed was contoured to obtain the estimated incidental dose to the primary site. Results: Median follow-up was 51 months (range, 13-155 months). The median radiation therapy (RT) dose to the neck was 6000 cGy (range, 5400-6400 cGy). The mean incidental dose to the primary tonsillar site was 4320 cGy (SD +/- 480 cGy) and to the primary base of tongue site was 4060 cGy (SD +/- 420 cGy). There were no local failures and only 1 regional failure, resulting in 97.5% locoregional control rate at 4 years. Two patients developed distant metastases, without evidence of locoregional recurrence, for a 4-year overall survival rate of 97%. Conclusions: Our analysis suggests that mucosal sparing RT after TOS in favorable risk oropharyngeal cancer patients may provide comparable oncologic and improved functional outcomes compared to conventional treatment in selected patients.