Comparison of survival according to chemotherapy regimen among patients in group 1. (A) OS between patients receiving CHOP vs those receiving augmented CHOP based on SNUH data. (B) PFS between patients receiving CHOP vs those receiving a CHOP-like regimen based on SNUH data. (C) OS between patients receiving CHOP vs those receiving a CHOP-like regimen based on KCCR data. (D) PFS between patients receiving CHOP vs those receiving a CHOP-like regimen based on KCCR data.