Investigation of long-term survival outcomes and failure patterns of patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy: a retrospective analysis

// Wei Zhao 1, * , Hao Lei 1, 2, * , Xiaodong Zhu 1 , Ling Li 1 , Song Qu 1 , Xia Liang 1 1 Department of Radiation Oncology, Cancer Hospital of Guangxi Medical University, Nanning, 530021, China 2 Department of Radiation Oncology, Hubei Cancer Hospital, Wuhan, 430079, China * Wei Zhao and Hao Lei are co-first authors Correspondence to: Xiaodong Zhu, email: zhuxidonggxmu@126.com Keywords: failure pattern, intensity-modulated radiotherapy, long-term outcome, nasopharyngeal carcinoma, retrospective analysis Received: August 16, 2016 Accepted: November 07, 2016 Published: November 24, 2016 ABSTRACT Intensity-modulated radiotherapy (IMRT) has replaced the conventional radiotherapy (2D-RT) and improved clinical efficacy in Nasopharyngeal Carcinoma (NPC) patients. In the present study, we retrospectively analyzed the clinical characteristics of patients with NPC treated with IMRT to assess the long-term survival outcomes and failure patterns. Of the 527 patients, One hundred and twenty-one patients experienced treatment failure, 86 patients developed distant metastases, and 12 patients developed a second primary tumor. The local and regional recurrence rates were 31.4% and 14.0%, respectively. The 5-year overall survival (OS), progression-free survival (PFS), local recurrence-free survival (LRFS), regional relapse-free survival (RRFS), and distant metastatic relapse-free survival (DMFS) rates were 80.9%, 75.6%, 91.7%, 96.2%, and 83.0%, respectively. The 5-year LRFS rates of Stage T1-4 patients were 100.0%, 93.1%, 92.0%, and 85.8%, respectively. The 5-year DMFS rates of Stage N0-3 patients were 95.0%, 86.1%, 79.5%, and 67.2%, respectively. Multivariate analysis showed age and T-stage were independent predictors of OS, T-stage was an independent predictor of LRFS, and age and N-stage were independent predictors of PFS and DMFS. In summary, the improved treatment results with IMRT are primarily due to the achievement of a higher local tumor control rate and OS in NPC patients. However, distant metastasis was the most commonly observed failure pattern after treatment. These results provide deep insights about the value of IMRT in the treatment and prognosis of NPC patients.