Mucosal Sparing Radiation Therapy in Resected Oropharyngeal Cancer

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).

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.

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%.

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.