Assessment of Radiation-Induced Xerostomia in Patients of Head and Neck Cancers: A Comparative Study of Three-Dimensional Conformal Radiotherapy and Intensity Modulated Radiotherapy

Abstract

Introduction: Radiotherapy is a cornerstone in the management of head and neck cancers, but radiation-induced xerostomia remains one of the most common and debilitating late toxicities, significantly affecting long-term quality of life. With the advent of conformal radiotherapy techniques, particularly intensitymodulated radiotherapy (IMRT), better sparing of salivary glands has been achieved compared to three-dimensional conformal radiotherapy (3DCRT). This study aimed to compare the incidence, severity, and recovery of radiation-induced xerostomia between 3DCRT and IMRT using objective, subjective, and quantitative assessment tools. Materials and Methods: This prospective randomized study included 50 previously untreated patients with locally advanced head and neck cancers, randomly assigned to receive either 3DCRT (Group I, n=25) or IMRT (Group II, n=25). All patients received a total dose of 70 Gy in 35 fractions over 7 weeks with concurrent weekly cisplatin (35 mg/m²). Xerostomia was assessed at baseline, at completion of radiotherapy, and at 3 and 6 months post-treatment using RTOG morbidity criteria (objective), EORTC H&N35 quality-of-life questionnaire (subjective), and the Saxon test for quantitative salivary flow measurement. Parotid mean doses were recorded and correlated with xerostomia outcomes. Statistical analysis was performed using the chi-square test, with p < 0.05 considered significant. Results: At completion of radiotherapy, both groups demonstrated a significant reduction in salivary flow rates with no statistically significant difference in acute xerostomia. During follow-up, recovery of salivary function was observed in both groups; however, the IMRT group showed significantly better recovery at 3 months (p = 0.02) and 6 months (p = 0.01). Quantitative salivary flow rates at 6 months approached baseline values more closely in the IMRT group. Although objective RTOG xerostomia grades did not show a statistically significant difference between the two groups, subjective assessment using EORTC H&N35 revealed significantly better quality-of-life scores in the IMRT group for head and neck pain, swallowing, speech, and sensory domains. Mean parotid doses