Locoregional radiotherapy in patients with distant metastases of nasopharyngeal carcinoma at diagnosis

Systemic chemotherapy is the basic palliative treatment for metastatic nasopharyngeal carcinoma(NPC); however, it is not known whether locoregional radiotherapy targeting the primary tumor and regional lymph nodes affects the survival of patients with metastatic NPC. Therefore, we aimed to retrospectively evaluate the benefits of locoregional radiotherapy. A total of 408 patients with metastatic NPC were included in this study. The mortality risks of the patients undergoing supportive treatment and those undergoing chemotherapy were compared with that of patients undergoing locoregional radiotherapy delivered alone or in combination with chemotherapy. Univariate and multivariate analyses were conducted. The contributions of independent factors were assessed after adjustment for covariates with significant prognostic associations (P<0.05). Both locoregional radiotherapy and systemic chemotherapy were identified as significant independent prognostic factors of overall survival(OS). The mortality risk was similar in the group undergoing locoregional radiotherapy alone and the group undergoing systemic chemotherapy alone [multi-adjusted hazard ratio(HR)=0.9, P=0.529]; this risk was 60% lower than that of the group undergoing supportive treatment(HR=0.4, P=0.004) and 130% higher than that of the group undergoing both systemic chemotherapy and locoregional radiotherapy(HR=2.3, P<0.001). In conclusion, locoregional radiotherapy, particularly when combined with systemic chemotherapy, is associated with improved survival of patients with metastatic NPC.