Dose to Dysphagia–Aspiration-related Structures and Its Effect on Dysphagia in Patients of Carcinoma Oropharynx: Three-dimensional Conformal Radiotherapy versus Intensity-modulated Radiotherapy: A Prospective Study

Abstract

ABSTRACT Objective: The aim is to assess the radiation dose received by the dysphagia–aspiration-related structures (DARS) and radiation-related dysphagia in intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) arms and compare the results between both the techniques in patients with oropharyngeal cancer. Materials and Methods: A hospital-based prospective approach and histologically proven oropharyngeal carcinoma patients were selected for the analysis. A total of 30 patients were equally allocated to the two treatment arms: Intensity-modulated radiotherapy (IMRT) and 3-Dimensional conformal radiotherapy (3DCRT). Patients were treated to a dose of 70 Gy in 35 fractions with or without chemotherapy. DARS comprises superior pharyngeal constrictor muscle, middle pharyngeal constrictor muscle, inferior pharyngeal constrictor muscle, larynx, and esophagus. Results: IMRT has shown an advantage over 3DCRT in reducing the dose to the DARS with significant P values (except for the esophagus). The P value of DARS was significant for V30, V65, V70, D50, and D80, whereas the P value was insignificant for V50 and V60. Dysphagia in the 3DCRT arm was higher in grades than in the IMRT arm when assessed with the National Cancer Institute common terminology criteria for adverse events, version 5.0 (CTCAE v5.0) grading system. Conclusion: IMRT has an advantage over 3DCRT in terms of the dose received by the DARS, resulting in reducing the incidence of dysphagia. It is improving the quality of life of patients with oropharyngeal cancers.