Cox proportional hazards regression analysis for OS from risk-defining events of patients with relapsed and primary refractory (R/R) MTCL and MNKCL. Forest plot of univariable and multivariable analysis for risk factors associated with survival. (A) Univariable analysis performed systematically on 21 clinically relevant factors on the global training and test data sets and C-index reported. The 6 features used in the final multivariable model are highlighted in red. (B) Final multivariable model selected based on the highest training C-index among the models that incorporated covariates retaining an independent prognostic value (P ≤ .05). Included covariates were age >60 years, primary refractory, not AITL subtype, >1 extranodal site involvement, Ki67 ≥40%, and ALC less than LLN. ALC, absolute lymphocyte count; β2M, beta-2 microglobulin; CRP, C-reactive protein; ECOG, Eastern Cooperative Oncology Group; IgG, Immunoglobulin G; LLN, lower limit of normal; Tx, treatment; ULN, upper limit of normal.