[Radiation encephalopathy in nasopharyngeal carcinoma patients in mainland China: a systematic evaluation].

OBJECTIVE: To evaluate the clinical characteristics of radiation encephalopathy in nasopharyngeal carcinoma (NPC) patients of mainland China. METHODS: Based on the principle of systematic review, the search for literature in computerized Chinese Biology & Medicine database, 1979 to June 2001 (CBM) was performed, with the papers appraised according to conformation criteria, the methodological quality of the studies analyzed, and clinical data of patients processed using the statistical model. RESULTS: 553 cases accumulated from 18 identified articles submitted by 16 hospitals in China were analyzed. The mean incidence of encephalopathy diagnosed by CT or MRI was 1.9% (0.4% - 2.6%). The disease focus was located in the temporal lobe (80%) and in the brain stem (17%). The mean dose received in the first course of radiotherapy to the nasopharynx or skull base was 72.9 Gy, and the latent period of this disease was 3.6 years. CONCLUSION: The probability of encephalopathy after radiation for nasopharyngeal carcinoma in mainland China is reported in this review. Multi-center case-control or Cohort studies are required in the future.