Intensity-modulated radiotherapy vs. parotid-sparing 3D conformal radiotherapy. Effect on outcome and toxicity in locally advanced head and neck cancer

Abstract

Background and purpose: Intensity-modulated radiotherapy (IMRT) has rapidly become standard of care in the management of locally advanced head and neck squamous cell carcinoma (HNSCC). In this study, our aim was to retrospectively investigate the effect of the introducing IMRT on outcome and treatment-related toxicity compared to parotid-sparing 3D conformal radiotherapy (3DCRT).

Material and methods: A total of 245 patients with stage III and IV HNSCC treated with primary radiotherapy between January 2003 and December 2010 were included in this analysis: 135 patients were treated with 3DCRT, 110 patients with IMRT. Groups were compared for acute and late toxicity, locoregional control (LRC), and overall survival (OS). Oncologic outcomes were estimated using Kaplan-Meier analysis and compared using a log-rank test. Acute toxicity was analyzed according to the Common Terminology Criteria for Adverse Events v3.0 and late toxicity was scored using the RTOG/EORTC late toxicity scoring system.

Results: Median follow-up was 35 months in the IMRT group and 68 months in the 3DCRT group. No significant differences were found in 3-year LRC and OS rates between the IMRT group and 3DCRT group. Significantly less acute mucositis ≥ grade 3 was observed in the IMRT group (32% vs. 44%, p = 0.03). There was significantly less late xerostomia ≥ grade 2 in the IMRT group than in the 3DCRT group (23% vs. 68%, p < 0.001). After 24 months, there was less dysphagia ≥ grade 2 in the IMRT group although differences failed to reach statistical significance.

Conclusion: The introduction of IMRT in the radiotherapeutic management of locally advanced head and neck cancer significantly improved late toxicity without compromising tumor control compared to a parotid-sparing 3D conformal radiotherapy technique.