The Outcomes of Intensity Modulated Radiotherapy versus Conventional 2D Radiotherapy in Patients with Oropharyngeal or Hypopharyngeal Squamous Cell Carcinoma. A Case-Control Study

Abstract

"Introduction: Head and neck cancers’ radiotherapy (RT) is challenging due to the irregular target volumes and the proximity of multiple organs at risk. The purpose of this study is to compare the toxicity, loco-regional control and the pattern of tumour recurrence after intensity modulated radiotherapy (IMRT) or conventional 2D radiotherapy (2D CRT) in patients with squamous cell carcinoma (SCC) oropharyngeal or hypopharyngeal cancers. Material and method: We retrospectively compared the outcomes of SCC oropharyngeal or hypopharyngeal cases treated by IMRT or 2D CRT from 1998 to 2010 in a Canadian Academic Hospital. We matched the patients in the two groups according to primary tumour location and clinical stage. The information on treatment, toxicity and outcomes was retrieved from patients’ medical records. For the patients having a recurrence after IMRT, the CT scan at relapse was fused with the planning CT. For the patients recurring after 2D CRT, we matched the CT images with the relative position of the radiotherapy fields. Statistical analysis was made using GraphPad Prism software. Results: We included a total of 50 patients in the IMRT group and 50 in the 2D CRT group. The median age was 62 and 58 years, respectively, and the median follow-up was 18 and 22.6 months, respectively. Some of the side effects were less frequent on the IMRT group compared to the 2D CRT: xerostomia (16% vs 64%, P=0.0036), mucositis (70% vs 74% P=0.5451), weight loss (18% vs 46% P= 0.0027), radionecrosis/mandibular fracture (0 % vs 2%), fibrosis (0% vs 10%), and telangiectasia (0% vs 4%). However, acute dermatitis and late dysphagia were more frequent in the IMRT group (44% vs 28% P=0.0042; and 14% vs 2% P=0.028; respectively). The overall survival at 2 years was for 74.03% for IMRT and 60% for 2D CRT (P< 0.001) and the 5 years actuarial locoregional control was 89.54 % for IMRT group, and 62.48% for the 2DCRT group (P< 0.001). Three patients from the IMRT group had a local recurrence (2 in-field and 1 marginal), while in the 2D-CRT group, there were 10 patients with a local recurrence (6 in-field and 4 marginal). Conclusion: SCC oropharyngeal and hypopharyngeal patients treated with IMRT and concurrent cisplatin had better outcomes and fewer side effects, when compared to similar cases treated with 2D CRT. The local recurrence had a similar pattern for both techniques."