Salivary Function and Quality of Life Following Adaptive Intensity-Modulated Radiotherapy for Locally Advanced Head and Neck Cancer

Background: Intensity-modulated radiotherapy (IMRT) is the standard treatment for locally advanced head and neck cancer (LAHNC). However, the potential role of adaptive radiotherapy in preserving salivary function and enhancing quality of life (QoL) remains underexplored. Aim: This study aimed to assess salivary function and QoL following offline adaptive IMRT in patients with LAHNC undergoing concurrent chemotherapy. Methods: Salivary function and QoL were evaluated during the last follow-up in LAHNC patients treated with a single offline adaptive IMRT. Unstimulated salivary flow rate (uSFR) was measured to assess salivary function, while QoL was evaluated using the EORTC QLQ-HN43 questionnaire. Results: A total of 43 patients (median age: 56 years; range: 19–74) were included. Adaptive IMRT improved GTV100% and PTV95% coverage by 0.2% and 1.27%, respectively, while reducing the mean doses to the right and left parotid glands by 3.86% and 5.32%. Grade III-IV treatment-related toxicity occurred in 44% of patients. After a median follow-up of 34.8 months (range: 8.5–45.5), the 3-year disease-free and overall survival rates were 66.5% and 83%, respectively. Among the 29 assessed patients, all regained normal salivary flow (>1 ml/min), with a median uSFR of 3.3 ml/min (range: 1.5–7.4). Quality of life evaluation revealed improvements in dry mouth, sticky saliva, and 11 other scales, though four scales worsened, and two remained unchanged. Conclusion: This phase II study suggests that a single offline adaptive IMRT approach may enhance target volume coverage, improve parotid gland sparing, and support salivary function recovery and QoL in LAHNC patients.