1054PD - A New Classification for Nasopharyngeal Carcinoma

Abstract

Background: This study is to develop and validate a new classification for nasopharyngeal carcinoma (NPC). Methods: Fifteen hundred and twenty-eight (1528) newly diagnosed NPC patients treated between 1995 and 2010 were included in this study. Seven hundred and one patients (n = 701) were treated with 3D conformal radiotherapy (3D-RT) and 827 patients were treated with IMRT. Cox proportional hazards model was used to select the significant split node to partition patients into the different risk group. Recursive partitioning analysis derived a new classification in patients treated with 3D-RT objectively. This new staging system was then validated in patients treated with IMRT. Results: The median follow-up interval was 84.6 months (ranging 2-175 months). According to the 7th AJCC staging system, the stage I patients showed a 5-year overall survival (OS) rate of 93.0%, stage II of 94.5%, stage III of 87.5%, stage IVA of 71.5%, stage IVB of 61.3%, and stage IVC of 5.8% (p < 0.0001). In the validation group (n = 827), the Group I in new system was patients with stages of T1-3N0-1 and T1N2 (n = 364); their 5-year OS was 92.4%. The Group II was patients with stages of T2N2 and T3N2 (n = 175); thier 5-year OS was 86.0%. The Group III was patients with stages of any T4 and N3 (n = 249); their 5-year OS was 72.0%. The Group IV was patients with distant metastasis (n = 36); their 5-year OS was 17.9%. This new classification system will be compared to the 8th AJCC staging system. Conclusions: We propose a new staging system for NPC, which distributes more patients in the early stage.Table1054PD Patient Distribution According to Chinese 2008 and the 7th AJCC staging systemsStageChinese 2008 staging2010 AJCC stagingCurrent proposalStage I2.3%2.3%42.9%Stage II11.0%23.7%21.9%Stage III39.4%49.1%30.0%Stage IV47.3%24.9%5.2% Open table in a new tab Legal entity responsible for the study: None Funding: Koo Foundation Sun Yat-Sen Cancer Center Disclosure: All authors have declared no conflicts of interest.