RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: External-use traditional Chinese medicine (TCM) agents are widely used to relieve the adverse effects of radiation therapy in nasopharyngeal cancer patients. AIM OF THE STUDY: Our study aimed to evaluate the influence of external-use TCM agents to relieve radiotherapy-related adverse effects on the efficacy of radiation therapy and the prognosis of nasopharyngeal cancer patients. MATERIALS AND METHODS: By using the Chang Gung Research Database (CGRD), we analyzed 1823 newly diagnosed nasopharyngeal cancer patients with radiotherapy-related adverse effects between 2001/01 and 2015/12. We used Kaplan-Meier analysis and a Cox regression model to estimate the differences in effects on survival outcomes between two groups, TCM external users and non-TCM external users. RESULTS: We found that TCM external users had significantly better 3-year and 5-year overall survival rates (log-rank test, p = 0.0377 and p = 0.034, respectively) than non-TCM external users. The 3-year and 5-year disease-free survival rates were not statistically significantly different between the groups. We also found a trend of improved 3-year and 5-year overall survival rates in TCM external users with advanced-stage disease, without statistical significance (log-rank test, p = 0.10 and p = 0.089, respectively). The subgroup analysis revealed lower risks of mortality in TCM external users among the nonhypertension, nonhyperlipidemia, nonischemic heart disease, noncirrhosis, and nonchronic kidney disease groups. CONCLUSIONS: Our study showed that TCM agents external use could significantly improve 3-year and 5-year overall survival rates in nasopharyngeal cancer patients with radiotherapy-related adverse effects.