Survival Outcomes Of Patients With Metastatic Nasopharyngeal Carcinoma Based On Intensity-modulated Radiotherapy

Objective: To investigate the clinical characteristics,treatment pattern,survival status and prognosis factors of metastatic nasopharyngeal carcinoma(m NPC)in the era of intensity-modulated radiotherapy(IMRT).Methods: Between 2006 and 2015,data on 236 patients who had been diagnosed with m NPC at Nanjing Medical University Affiliated Cancer Hospital of China were retrospectively analysed in this study.All patients underwent radical IMRT for nasopharyngeal and cervical primary lesions.For metastatic lesions,90 received chemotherapy alone,local treatments were performed in 146 patients.The Kaplan-Meier method was used to calculate the survival rate,and the Log-rank method and the Cox risk ratio model were used to analyze the prognostic factors of univariate and multivariate analysis respectively.Results: With a median follow-up time of 22 months,the 1-,2-,and 3-year Overall metastasis survival(OMS)rate were 79.9%,48.4% and 36.5%,respectively.The disease-free interval(DFI),number of metastases,treatment modality,and number of chemotherapy cycles are independent prognostic factors affecting OMS in m NPC.The survival of NPC with metastasis at initial diagnosis is better than who developed metastasis after their initial definitive treatment.The prognosis of metastasis detected within 6 months after initial treatment is especially poor.The incidence of oligometastases was 59.7%,and the prognosis was significantly better than that of patients with multiple metastases.Long-term survival,even clinical cure could be achieved through comprehensive metastasis-directed treatments.Conclusion: Long-term survival can be achieved in patients with distant metastasis at initial diagnosis after systemic chemotherapy combined with definitive IMRT for primary tumors.The metastasis diagnosis after primary radical treatment may benefit from local treatment of metastatic lesions combined with chemotherapy.There is no effective measures of stratitied therapy and clinical diagnostic criteria for oligometastases.Optimal therapeutic sequence and strategy for m NPC may be best assessed in prospective randomized trials.