Higher dose per fraction and shorter overall treatment time using intensity-modulated radiation therapy versus conventional radiation therapy with concurrent carboplatin and 5-fluorouracil for locally advanced oropharyngeal carcinoma: A comparison of toxicity and efficacy

Abstract

6038 Background: The aim of this retrospective study was to compare toxicity and efficacy of two different radiotherapy regimens, the first one using intensity-modulated radiation therapy (IMRT) to that of conventional radiotherapy (CRT) in patients treated with concomitant chemotherapy for locally advanced oropharyngeal cancer. Methods: Between January 2000 and December 2007, 249 patients with stage III-IV squamous cell oropharyngeal carcinoma were treated at our institution with definitive concurrent chemoradiation using carboplatin 70 mg/m2/day for four days and 5-fluorouracil 600 mg/m2/day as a continuous infusion every 3 weeks. One hundred patients had 70 Gy in 33 fractions using IMRT (2.12 Gy per day) and 149 received CRT at 70 gy in 35 fractions (2 Gy per day), both administered five times a week. Toxicities were compared using Fisher's exact test. Overall survival (OS), disease-free survival (DFS), and locoregional control (LRC) were estimated using the Kaplan-Meier method and compared with the log-rank test. Results: Median follow-up was 33 months. Three year actuarial rates for OS, DFS, and LRC were 95.4 vs. 75.8% (p < 0.001), 89.3 vs. 71.6% (p < 0.001), and 92.4 vs. 85.3% (p = 0.050) for IMRT and CRT respectively. To minimize the effect of changes in treatment paradigm over time, analyses were performed for patients treated after January 2004 and still showed OS, DFS, and LRC differences. Comparison of toxicities demonstrated that IMRT was associated with fewer dermatitis than CRT (p < 0.01), but caused the same rates of mucositis, weight loss, enteral feeding, hospitalization and death during treatment. There was significantly less xerostomia at 24 and 36 months (p < 0.001) following the end of treatment with IMRT. Conclusions: In this retrospective study, higher dose per fraction and shorter overall treatment time using IMRT given concurrently with chemotherapy when compared to CRT is a safe regimen with better OS, DFS, LRC, and less long term xerostomia. Altered fractionation RT with chemotherapy seems to result in better outcome and future prospective trials are needed to confirm this hypothesis. No significant financial relationships to disclose.