Intensity-modulated radiation therapy (IMRT) for advanced oropharyngeal carcinoma: The MSKCC experience

Abstract

5513 Background: Retrospective review of an institution’s experience using IMRT for advanced oropharyngeal carcinoma. Methods: Between 9/98 and 6/04, 43 patients with oropharyngeal cancer underwent definitive IMRT at our institution. The disease was stage III in 7 (16%), and stage IV in 36 (84%) patients. Concurrent chemotherapy (CT) was used in 95% and consisted of planned 2–3 cycles every 3–4 weeks of cisplatin (100 mg/m2 IV in 71%), or carboplatin/5-fluorouracil (70 mg/m2/day IV and 600 mg/m2/day continuous infusion, both for 4 days, in 29%). Patients were treated using 2 different IMRT approaches: 74% Dose Painting and 26% Concomitant Boost (CB). The prescription dose to the gross tumor was 70 Gy. Feeding tubes (PEGs) were placed before treatment in 91% of the patients. Acute toxicity and late xerostomia were graded according to the RTOG radiation morbidity scoring criteria. Other complications were evaluated using subjective criteria such as the presence of esophageal stricture and the need for PEG usage. The local (LPF), regional progression-free (RPF), distant metastases-free (DMF) rates, and overall survival (OS) were calculated using Kaplan-Meier method. Median follow-up was 15.2 months (range 5.8–74). Results: The 2-year estimates of LPF, RPF, DMF and OS were 97.2%, 85%, 72.4% and 100% respectively. Two patients required a RT treatment break. The worst acute mucositis experienced were Grade 1 in 2 (5%), Grade 2 in 22 (51%), and Grade 3 in 19 (44%) patients. Xerostomia decreased with time and among the patients (22) with at least 9 months of follow up there were 68% of Grade 0–1 and 32% of Grade 2 toxicity. Of the 39 patients who required upfront PEG placement, 6 were still using PEGs for nutrition at the time of this analysis. Two patients had cervical esophageal strictures: one was still PEG dependent 1 year post treatment, and the other required routine esophageal dilatations. Both were treated using CB. There was no difference in the time to end PEG nutrition between both IMRT groups (p=0.9). Conclusions: In these preliminary results, IMRT achieved encouraging local control rates in patients with advanced oropharyngeal carcinoma. Treatment toxicity was acceptable in the setting of concomitant CT. No significant financial relationships to disclose.