Predictors of severe late radiotherapy-related toxicity after hyperfractionated radiotherapy with or without concomitant cisplatin in locally advanced head and neck cancer. Secondary retrospective analysis of a randomized phase III trial (SAKK 10/94)

Abstract

Background and purposeThis secondary analysis was performed to identify predictive factors for severe late radiotherapy (RT)-related toxicity after treatment with hyperfractionated RT +/− concomitant cisplatin in locally advanced head and neck cancer. Materials and methodsPatients were retrospectively analyzed from the previously reported randomized phase III trial: SAKK 10/94. Severe late RT-related toxicity was defined as late RTOG ⩾ grade 3 toxicity starting 3months after end of RT and/or potential treatment-related death within 3years of randomization. ResultsTwo hundred and thirteen randomized patients were analyzed; 84 (39%) experienced severe late RT-related toxicity. With median follow-up of 9.7years (range, 0.4–15.4years), median time to severe late RT-related toxicity was 9.6years. In the univariate Cox proportional hazards model the following variables were associated with severe late RT-related toxicity: advanced N-classification (p<0.001); technically unresectable disease (p=0.04); weight loss ratio (p=0.003); supportive measures (p=0.009) and severe acute dysphagia (p=0.001). In the subsequent multivariate analysis all variables except use of supportive measures remained statistically significant. ConclusionsChemotherapy did not appear to affect severe late RT-related toxicity, but advanced N-classification, technically unresectable disease, weight loss ratio, and severe acute dysphagia were independent predictive factors for severe late RT-related toxicity.