The impact of treatment modality and radiation technique on outcomes and toxicity of patients with locally advanced oropharyngeal cancer.

Objectives/hypothesis: To investigate the impact of treatment modality and radiation technique on oncologic outcomes and toxicity of patients with locally advanced oropharyngeal cancer (OPC).

Study Design: Retrospective analysis of outcomes and toxicity.

Methods: Between 2000 and 2011, 204 consecutive patients with locally advanced OPC were treated with definitive (chemo)radiotherapy using 3-dimensional conformal (3DCRT) or intensity-modulated radiotherapy (IMRT). Endpoints were local control (LC), regional control (RC), disease-free survival (DFS), cause-specific survival (CSS), and overall survival (OS), and toxicity.

Results: After a median follow-up of 44 months (range 4-134), the 5-year Kaplan-Meier estimates of LC, RC, DFS, CSS, and OS were 78%, 92%, 60%, 64%, and 48%, respectively. Grade 3 mucositis and dysphagia (feeding-tube dependency) were reported in 75% and 65%, respectively. The overall incidence of grade ≥ 2 and grade 3 late toxicities were 44% and 16%, respectively. Dysphagia and xerostomia were the most frequently reported late toxicity. Chemotherapy was significantly predictive for improved outcomes and increased toxicity. IMRT was significantly correlated with reduced toxicity.

Conclusions: Compared to radiation alone, chemoradiotherapy significantly improved oncologic outcomes, but with significantly increased toxicity. Compared to 3DCRT, the introduction of IMRT resulted in a significant reduction of acute and late toxicity with slightly better, or at least comparable, outcomes. Despite the improvements achieved by the implementation of chemo-IMRT, different new strategies to further improve outcome and reduce toxicity need to be thoroughly investigated in prospective, preferably, randomized trials.