Long Term Outcomes and Prognostic Factors of N0 Stage Nasopharyngeal Carcinoma: a Single Institutional Experience with 610 Patients

Treatment responses of N0 stage nasopharyngeal carcinoma were firstly analyzed comprehensively toevaluate long term outcomes of patients and identify prognostic factors. A total of 610 patients with N0 NPC,undergoing definitive radiotherapy to their primary lesion and prophylactic radiation to upper neck, werereviewed retrospectively. Concomitant chemotherapy was administrated to 65 out of the 610. Survival rates ofthe patients were calculated using the Kaplan-Meier method and compared by log-rank test. Prognostic factorswere identified by the Cox regression model. The study revealed the 5-year and 10-year overall, disease-free,disease-specific, local failure-free, regional failure-free, locoregional failure-free and distant metastasis-freesurvival rates to be 78.7% and 66.8%, 68.8% and 55.8%, 79.9% and 70.4%, 81.2% and 72.5%, 95.8% and91.8%, 78.3% and 68.5%, 88.5% and 85.5%, respectively. There were 192 patients experiencing failure (31.5%)after radiotherapy or chemoradiotherapy. Of these, local recurrence, regional relapse and distant metastases asthe first event of failure occurred in 100 (100/610, 16.4%), 15(15/610, 2.5%) and 52 (52/610, 8.5%), respectively.Multivariate analysis showed that T stage was the only independent prognostic factor for patients with N0NPC (P=0.000). Late T stage (P=0.000), male (P=0.039) and anemia (P=0.007) were independently unfavorablefactors predicting disease-free survival. After treatment, satisfactory outcome wasgenerally achieved in patientswith N0 NPC. Local recurrence represented the predominant mode of treatment failure, while T stage was theonly independent prognostic factor for overall survival. Late T stage, male gender, and anemia independentlypredicted lower possibility of the disease-free survival.