Definitive radiotherapy for nasopharyngeal carcinoma in Japan: analysis of cases in the National Head and Neck Cancer Registry from 2011 to 2014.

ABSTRACT

OBJECTIVE: This study aimed to analyze the nationwide prognosis of patients with nasopharyngeal carcinoma who underwent definitive radiotherapy in Japan, utilizing the National Head and Neck Cancer Registry data. METHODS: A total of 741 patients diagnosed with primary nasopharyngeal carcinoma were screened from 2011 to 2014. The inclusion criteria were histologically proven nasopharyngeal squamous cell carcinoma, receiving definitive radiotherapy, and no distant metastases. Patients with unclear prognoses or unknown staging were excluded. The primary endpoint was 5-year overall survival, and secondary endpoints were 5-year progression-free survival and survival by stage. RESULTS: A total of 457 patients met the inclusion criteria. The median age was 60 years, and 80% were male. The proportions of patients with performance status 0, 1, 2 and 3 were 69, 10, 1 and 1%, respectively. Chemoradiotherapy was administered to 84.7%. Radiotherapy modalities were recorded only for 29 patients (three received intensity-modulated radiotherapy and 26 received two/three-dimensional radiotherapy). Of those included, 7.4, 24.7, 35.7, 24.5 and 7.7% had Stage I, II, III, IVA and IVB disease, respectively. The 5-year overall survival was 72.5% for all patients 82.6, 86.6, 76.0, 51.4 and 66.5% for Stage I, II, III, IVA and IVB disease, respectively. The 5-year progression-free survival was 58.6% 75.6, 66.8, 61.5, 43.7 and 46.5% for Stage I, II, III, IVA and IVB disease, respectively. CONCLUSIONS: This nationwide survey demonstrated favorable prognoses and provided valuable foundational data for similar future surveys to monitor the penetration of appropriate treatment and changes in clinical structures based on new evidence.