ObjectiveTo explore the values of the apparent diffusion coefficient (ADC) measured by diffusion-weighted imaging and the 2017 staging system of nasopharyngeal carcinoma in the prognostic evaluation.MethodsClinical and imaging data of 90 nasopharyngeal carcinoma patients were retrospectively analyzed. The correlation between ADC values of primary tumor and T stages, N stages and clinical stages were evaluated. The median follow-up time was 54 months (5 to 90 months). According to the disease progression after chemoradiotherapy, they were divided into progressive group(29 cases) and non-progressive group(61 cases).ResultsThe ADC values of primary tumor of Ⅰ and Ⅱ stages were significantly higher than those of Ⅲ and IVa stages (P < 0.05). The ADC values of T1 and T2 stages were significantly higher than that of T4 stage(P < 0.05). Multivariate analysis showed that the risk of disease progression in Ⅳa stage was higher than those in Ⅰ to Ⅲ stages (OR=3.497, P=0.001).ConclusionsADC value of primary tumor is correlated with 2017 staging system of nasopharyngeal carcinoma in China. Clinical stage is a prognostic factor for disease progression.