Survival. Kaplan-Meier curves of (A) PFS and OS (B) in HIV-associated Burkitt lymphoma (HIV-BL) patients treated in the United States (US) and United Kingdom (UK). Kaplan-Meier curves of (C) PFS and (D) OS according to CD4 count at HIV-BL diagnosis. Kaplan-Meier curves of (E) PFS and OS (F) by BL–International Prognostic Index (age ≥40 years, LDH >3× ULN, ECOG PS ≥2, and CNS involvement). Group distribution: 11% in the low-risk (no risk factors), 31% in the intermediate-risk (1 factor), and 58% in the high-risk (≥2 factors) group.