Impact of Dose-Volume Parameters of Parotid Glands on Xerostomia in Patients Irradiated for Head-and-Neck Cancer

Abstract

Background/Aim: Optimal planning of radiotherapy for head-and-neck cancers should consider the risk of xerostomia. This study investigated the prognostic value of dose-volume parameters of the parotid glands. Patients and Methods: Dose-volume parameters were evaluated for xerostomia in 145 patients including D40 (minimum dose to 40% of corresponding parotid volume), D60 (minimum dose to 60%), D80 (minimum dose to 80%), and mean dose of ipsilateral, contralateral, and bilateral parotid glands. Results: Grade ≥2 xerostomia was significantly associated with D40 of ipsilateral and all parameters of bilateral glands; trends were found for all other parameters. Grade ≥3 xerostomia was significantly associated with D80 of bilateral glands; trends were found for other parameters of ipsilateral and bilateral glands. Conclusion: Since grade ≥2 xerostomia was associated with all parameters, D40, D60, and D80 did not provide additional information to mean doses. D80 of bilateral glands is a new factor and more predictive than mean dose regarding grade ≥3 xerostomia.