Long-term efficacy and adverse reactions of intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma in non-endemic northwest China

Objective To retrospectively analyze the characteristics of nasopharyngeal carcinoma, long-term efficacy, adverse reactions of intensity-modulated radiotherapy (IMRT) in non-endemic northwest China and summarize the experience of IMRT in the treatment of nasopharyngeal carcinoma in the past decade. Methods Clinical data of 658 patients newly diagnosed with nasopharyngeal carcinoma without distant metastasis admitted to First affiliated hospital from January 2006 to December 2016 were retrospectively analyzed. All patients were treated with IMRT. The survival analysis was performed by Kaplan-Meier method. The multivariate analysis was conducted with Cox’s regression model. Results In non-endemic northwest China, a large proportion of patients were newly diagnosed with locally advanced nasopharyngeal carcinoma, and a majority of them were pathologically characterized as differentiated subtypes. The 5-year overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS) and distant metastasis-free survival (DMFS) rates were 75.7%, 70.1%, 91.2%, 97.0% and 81.0%, respectively. Multivariate analysis showed that age, pathological type, nasopharyngeal tumor volume>23 cm3 and neck lymph node metastasis complicated with necrosis were the factors of poor prognosis of DFS (all P<0.05). Age, pathological type, neck lymph node metastasis complicated with necrosis were the factors of poor prognosis of OS (all P<0.05). N stage and neck lymph node metastasis complicated with necrosis were the factors of poor prognosis of DMFS (both P<0.05). Conclusions Similar clinical efficacy has been achieved in terms of IMRT for nasopharyngeal carcinoma in non-endemic northwest China compared with that in endemic area. Induction chemotherapy combined with concurrent radiochemotherapy can provide clinical benefits for patients with locally advanced nasopharyngeal carcinoma in non-endemic area. Key words: Nasopharyngeal neoplasm/intensity-modulated radiotherapy; Non-endemic area; Prognosis