ABSTRACT
PURPOSE: Previous studies demonstrated that the radiation therapy, image technology, and the application of chemotherapy have developed in the last 2 decades. This study explored the survival trends and treatment failure patterns of patients with nonmetastatic nasopharyngeal carcinoma (NPC) treated with radiation therapy. Furthermore, we evaluated the survival benefit brought by the development of radiation therapy, image technology, and chemotherapy based on a large cohort from 1990 to 2012. METHODS AND MATERIALS: Data from 20,305 patients with nonmetastatic NPC treated between 1990 and 2012 were analyzed. Patients were divided into 4 calendar periods (1990-1996, 1997-2002, 2003-2007, and 2008-2012). Overall survival (OS) was the primary endpoint. RESULTS: Magnetic resonance imaging has replaced computed tomography as the most important imaging technique since 2003. Conventional 2-dimensional radiation therapy, which was the main radiation therapy technique in our institution before 2008, was replaced by intensity modulated radiation therapy later. An increasing number of patients have undergone chemotherapy since 2003. The 5-year OS across the 4 calendar periods increased at each TNM stage with progression-free survival (PFS) and locoregional relapse-free survival (LRFS) showing a similar trend, whereas distant metastasis-free survival showed small differences. Multivariate analyses showed that the application of intensity modulated radiation therapy and magnetic resonance imaging were independent protective factors in OS, PFS, LRFS, and distant metastasis-free survival. Chemotherapy benefited patients in OS, PFS, and LRFS. The main pattern of treatment failure shifted from recurrence to distant metastasis. CONCLUSIONS: The development of radiation therapy, image technology, and chemotherapy increased survival rates among patients with NPC because of excellent locoregional control. Distant failure has become the greatest challenge for NPC treatment.
