A comparison of intensity-modulated radiation therapy and concomitant boost radiotherapy in the setting of concurrent chemotherapy for locally advanced oropharyngeal carcinoma

Purpose: The aim of this study was to compare toxicity/efficacy of conventional radiotherapy using delayed accelerated concomitant boost radiotherapy (CBRT) vs. intensity-modulated radiotherapy (IMRT) in the setting of concurrent chemotherapy (CT) for locally advanced oropharyngeal carcinoma.

Methods and Materials: Between September 1998 and June 2004, a total of 293 consecutive patients were treated at our institution for cancer of the oropharynx. Of these, 112 had Stage III/IV disease and squamous cell histology. In all, 41 were treated with IMRT/CT and 71 were treated with CBRT/CT, both to a median dose of 70 Gy. Most common CT was a planned two cycles given every 3 to 4 weeks of cisplatin, 100 mg/m² i.v., but an additional cycle was given to IMRT patients when possible. Both groups were well-matched for all prognostic factors.

Results: Median follow-up was 46 months (range, 3–93 months) for the CBRT patients and 31 months (range, 20–64 months) for the IMRT group. Three-year actuarial local-progression–free, regional-progression-free, locoregional progression-free, distant-metastases–free, disease-free, and overall survival rates were 85% vs. 95% (p = 0.17), 95% vs. 94% (p = 0.90), 82% vs. 92% (p = 0.18), 85% vs. 86% (p = 0.78), 76% vs. 82% (p = 0.57), and 81% vs. 91% (p = 0.10) for CBRT and IMRT patients, respectively. Three patients died of treatment-related toxicity in the CBRT group vs. none undergoing IMRT. At 2 years, 4% IMRT patients vs. 21% CBRT patients were dependent on percutaneous endoscopic gastrostomy (p = 0.02). Among those who had ≥20 months follow-up, there was a significant difference in Grade ≥2 xerostomia as defined by the criteria of the Radiation Therapy and Oncology Group, 67% vs. 12% (p = 0.02), in the CBRT vs. IMRT arm.

Conclusion: In the setting of CT for locally advanced oropharyngeal carcinoma, IMRT results in lower toxicity and similar treatment outcomes when compared with CBRT.

Keywords: IMRT, Oropharyngeal carcinoma, Concomitant boost, Intensity-modulated, Head-and-neck cancer