[Comparison of Different Staging Systems of Extranodal NK/T Cell Lymphoma and Prognosis Analysis]

To compare the value of Ann Arbor stage and CA stage in predicting the survival of extranodal NK/T cell lymphoma (ENKTL), and to explore its clinical features and prognosis.

The clinical data of 85 cases of newly diagnosed extranodal NK/T cell lymphoma diagnosed by histopathology in Shanxi Cancer Hospital from December 2012 to October 2023 were collected. All patients were staged using Ann Arbor staging and CA staging systems respectively. Receiver operating characteristic curve (ROC) was used to evaluate the predictive value of the two staging systems for progression-free survival (PFS) and overall survival (OS). Survival curves for the ENKTL patients were plotted using the Kaplan-Meier method and were judged by the log-rank test． Multivariate Cox regression model was used to analyze the influence of different clinical factors on prognosis.

The progression-free survival rate and overall survival rate was 68.2% and 76.5%, respectively. When using Ann Arbor staging system, 42 (49.4%), 19 (22.4%), 6 (7.1%), 18 (21.2%) patients were distributed in stages Ⅰ, Ⅱ, Ⅲ and Ⅳ. When CA staging system was used, the distribution of patients in stages Ⅰ, Ⅱ, Ⅲ and Ⅳ was 20 (23.5%), 22 (25.9%), 18 (21.2%) and 25 (29.4%). Kaplan-Meier survival curve and Log-rank test showed that when different staging systems were used to describe the cumulative PFS and OS rates in patients with ENKTL, the two staging systems could not significantly distinguish the survival curves of each stage. ROC curve results showed that CA staging system was better than Ann Arbor staging system in predicting PFS (AUC=0.762, P <0.001) and OS (AUC=0.719, P=0.003). Univariate analysis showed that treatment plan, regional lymph node and CA stage were the poor prognostic factors for ENKTL patients' FPS and OS, sex and Ann Arbor stage were the poor prognostic factors for PFS. By Cox multiple factors analysis, CA stage was an independent risk prognostic factor for OS (HR=5.106, 95%CI: 1.401-18.608, P=0.013), and regional lymph node involvement was an independent risk prognostic factor for PFS (HR=2.813, 95%CI: 1.039-7.618, P=0.042).

For ENKTL, CA stage is an independent prognostic factor for OS. Compared with Ann Arbor stage, the distribution of patients in each stage of CA stage is more balanced, which can better predict the PFS and OS of patients with ENKTL, and it can be considered as one of the criteria to guide the clinical staging of this disease.