OBJECTIVETo dynamically analyze the change of xerostomia in patients with nasopharyngeal carcinoma after radiotherapy by DW MRI.

METHODSTwenty-three nasopharyngeal carcinoma patients confirmed by pathology were enrolled. Male/Female: 19/4. The age was from 37 to 69 years. The patients were divided into two groups: G1, Dmean<26 Gy, G2, Dmean ≥ 26 Gy. All patients underwent salivary glands examination by DW MRI before IMRT, at the end of IMRT, 6 months and 12 months after IMRT, at the same time the ADC value of salivary glands were calculated. According to the RTOG/EORTC salivary gland injury grading standard and referring the subjective index, the degree of xerostomia was assessed. SPSS 13.0 and SAS 8.2 software were used to analyze the data.

RESULTSAt the end of IMRT, the change tendency of ADC in parotid and submandibular glands value was different in patients with different degree of xerostomia (F = 11.52, P < 0.01). At the end of IMRT, a significant difference for degree of xerostomia could be found in patients within different irradiation dose groups (Z = -3.622, P < 0.01). Clinical stage, treatment mode and age had no significant effect on the degree of xerostomia for patients at the end of IMRT (Z value was -0.791, -0.949, 2.488, all P > 0.05). A significant difference of xerostomia degree in patients was found at the various follow-up time after IMRT (χ(2) = 19.59, P < 0.01).

CONCLUSIONSThere is good correlation between the function of salivary gland and subjective rating of xerostomia in patients with nasopharyngeal carcinoma after radiotherapy. The degrees of salivary gland function and dry mouth in patients with nasopharyngeal carcinoma damage evaluate with illuminated dose increases. The function of salivary gland gradually restored and the degree of dry mouth gradually reduce with the extension of time after radiotherapy.