Survival analyses according to clinicopathological factors and development of an SPTCL risk stratification score. (A and B) The presence of the HAVCR2^Y82C mutation and age <30 years at diagnosis, respectively, were significant prognostic factors in patients with SPTCLs. (C) A tendency toward poor outcomes was observed in patients with tissue necrosis. (D-F) HLH (or HLH-like systemic illness), pSTAT3 positivity, and lower CCR4 expression were not significantly associated with RFS. (G) The risk score system integrating patients’ age and HAVCR2 status was significantly associated with RFS (P = .031). Patients with score 2 had a shorter RFS compared with patients with score 0 (log-rank test, P = .024). However, there were no significant differences between scores 2 vs 1 and scores 1 vs 2 (log-rank test, P = .068 and 0.354, respectively). (H) Significant correlation between the risk score and event of systemic complication was observed in the current study population (P = .005, linear-by-linear test) as well as in the pooled analysis using the published data from Gayden et al⁵  and Polprasert et al⁶  (P < .001, linear-by-linear test).