Abstract: Objective To explore the prognostic significance of C-reactive protein to albumin ratio for（CRP/Alb） extranodal NK/T cell lymphoma（ENKTL） treated with P-Gemox chemotherapy regimen combined radiotherapy. Methods The clinical data of 83 ENKTL patients treated in Sichuan Cancer Hospital from 2012 to 2017 were retrospectively analyzed. X-Tile software was used to calculate the cutoff value of CRP/Alb. According to the cutoff value，patients were divided into low CRP/Alb group（CRP/Alb<0.4，n=64） and high CRP/Alb group（CRP/Alb≥0.4，n=19）. Cox regression was used to analyze the relationship between CRP/Alb and prognosis. Results The 3-year progression-free survival（PFS） rate in the low CRP/Alb group was higher than that in the high CRP/Alb group（77.1% vs 30.7%，χ²=20.954，P<0.001），and the 3-year overall survival（OS） rate was also higher than in the high CRP/Alb group（87.4% vs 36.1%，χ²=22.559，P<0.001）. Multivariate Cox regression showed that CRP/Alb≥0.4 was an independent risk factor for PFS（HR=4.163，95%CI：1.899-9.128，P<0.001） and OS（HR=4.424，95%CI：2.026-9.662，P<0.001） in ENKTL patients. Further analysis showed that the median PFS and median OS of the low CRP/Alb group were higher than those of the high CRP/Alb group in both low-risk ENKTL patients and medium-high risk ENKTL patients（P<0.05）. Conclusion  The prognosis of patients with high CRP/Alb in early ENKTL treated with P-Gemox combined with radiotherapy is poor.

Key words: Extranodal NK/T cell lymphoma, C-reactive protein to albumin ratio, Prognosis