Long-term Therapeutic Outcome and Prognostic Factors of Patients with Nasopharyngeal Carcinoma Receiving Intensity-modulated Radiotherapy: An Analysis of 608 Patients from Low-endemic Regions of China

Objective To evaluate the long-term outcome and prognostic factors of patients with nasopharyngeal carcinoma (NPC) from low-endemic regions of China who received definitive intensity-modulated radiation therapy (IMRT). Methods The clinical data from 608 patients with newly-diagnosed non-metastatic NPC who have received initial treatment at our cancer center from January, 2008 to December, 2013 were retrospectively reviewed. All patients received definitive IMRT, and 87.7% received platinum-based chemotherapy. Results The median follow-up duration was 51 months (follow-up rate, 98.5%; range, 10-106 months) for the entire cohort. The 5-year overall survival rate was 79.7%. The 5-year local relapse-free survival rate, regional relapse-free survival rate, distant metastasis-free survival rate and progression-free survival rate were 92.4%, 93.3%, 79.2% and 74.3%, respectively. A total of 153 patients had experienced treatment failure, with distant metastasis as the primary cause in 77.1% (118/153). Patients with T4 or N3 diseases had a significantly poorer prognosis than other subcategories. Stage T4 and N3 were closely associated with distant metastasis, with the metastatic rate of 29.3% and 45.5%, respectively. Conclusion IMRT provides patients with non-metastatic NPC with satisfactory long-term survival. Both T stage and N stage are important prognostic factors for NPC patients. Patients with T4 or N3 diseases have significantly increased distant metastatic rates and poor survival time.