| Objective To evaluate the correlation of the initial volume of parotid glands with radiation-induced xerostomia in nasopharyngeal carcinoma(NPC)patients.Methods A total of 199 patients with nasopharyngeal carcinoma who were admitted to our hospital from September 2015 to March 2016 were enrolled in the study.According to the initial volume of parotid glands,all patients were divided into larger parotid group and smaller parotid group.The differences of dosimetric parameters of the parotid glands and the grade of xerostomia were compared between the two groups.The counting data adopt X2 test,the measurement data adopt t-test or nonparametric Mann-Whitney U-test,and non-parameter Mann-Whitney U-test for DVH index.Results There was no difference in the grade of xerostomia between the two groups at 3 and 6 months after radiotherapy.At 1-year after radiotherapy,the grade of xerostomia of the larger parotid group was lower(P=0.035).Otherwise,the smaller parotid group had higher delivered doses of the parotid.And there was no difference in the mean dose of submandibular glands between the two groups.Conclusions The initial volume of the parotid gland is one of the factors that affect the dryness rating after radiotherapy.The recovery of the parotid gland in the patients with larger parotid gland is better than that of the smaller parotid gland.For the smaller parotid gland patients,more attention should be paid to reduce the dose to protect the parotid gland. |
