Overall survival according to the combined biologic index (MIPI_b) in 220 patients with Ki-67 available. LR indicates low risk, combined biologic score (CBS) less than 5.7; IR, intermediate risk, CBS 5.7 or more but less than 6.5; and HR, high risk, CBS 6.5 or more. The combined biologic score is calculated as 0.03535 times age (years) plus 0.6978 (if ECOG > 1) plus 1.367 times log₁₀(LDH/ULN) plus 0.9393 times log₁₀(WBC count) plus 0.02142 times Ki-67 (%).