Impact of average weekly dose of radiation during radiotherapy alone or chemoradiotherapy in head and neck cancer.

Abstract

Altered fractionated radiotherapy (RT) has been shown to improve locoregional control (LRC) and overall survival (OS) in squamous cell cancer of the head and neck (SCCHN). We investigated patient outcomes using a new parameter: the average weekly dose (AWD). The medical records of 601 patients who received definitive RT for SCCHN were reviewed. AWD was calculated by dividing the total dose in Gray (Gy) by overall treatment time in weeks, and assessed for predictive value. Various standard RT fractionation schedules were used. An AWD >10.0 Gy was associated with improved LRC at 2 years for patients treated with RT alone (80.9% vs 60.9%; p = .006), but not for those treated with concurrent chemoradiation (75.3% vs 77.3%; p = .77). Nonsignificant increases in late dysphagia were seen with AWD >10.0 Gy. An AWD of >10 Gy was found to be beneficial for RT alone regimens but not chemoradiotherapy regimens.