Correlation of Dose-volume Parameters of Pharyngeal Constrictor Muscles with Acute Dysphagia in Intensity-modulated Radiation Therapy for Oropharyngeal Cancer

A BSTRACT Objective: Dysphagia is a prevalent side effect in patients with head-and-neck cancers undergoing radiotherapy (RT), impacting individuals both during and after treatment. For many patients receiving organ-preserving therapies, long-term swallowing difficulties can significantly affect their quality of life. We conducted this study to assess the frequency and severity of acute dysphagia and explore the correlation between these outcomes and dose-volume histograms (DVHs) of the pharyngeal constrictor muscles (PCMs). Materials and Methods: This study conducted a retrospective analysis of patients diagnosed with carcinoma oropharynx who underwent intensity-modulated radiation therapy with concurrent chemotherapy at the Department of Radiation Oncology, Father Muller Medical College, Mangalore, between September 2022 and March 2024. Data were collected from the electronic medical records, including patient demographics, clinical staging, details of the chemoradiation regimen, and dysphagia during treatment. DVHs of PCMs were correlated with acute dysphagia. Results: The study included a total of 32 patients diagnosed with carcinoma oropharynx who received definitive chemoradiation therapy. At the end of treatment, 65.6% of patients developed Grade 3 dysphagia and 34.4% of patients developed Grade 2 dysphagia. The D MEAN to PCM for Grade 2 dysphagia was 64.2 Gy, while for Grade 3 dysphagia, it was 65.1 Gy. V50 was 88.7% for Grade 2 dysphagia and 89.0% for Grade 3 dysphagia, while V60 was 77.8% for Grade 2 and 81.3% for Grade 3 dysphagia. All comparisons were statistically nonsignificant. Conclusion: The study found no significant correlation between acute dysphagia and the mean doses to the PCMs, as well as V50 and V60 values for these muscles. However, reducing the RT dose to the constrictor muscles may offer a potential benefit in preventing severe dysphagia.