MegaCHOP treatment protocol. Cumulative doses per course were given. Dose of etoposide at DL2 is set in brackets; all other drugs were given at identical doses at DL1 and DL2. PBPC indicates peripheral blood progenitor cell; CYC, cyclophosphamide; DOX, doxorubicin; VCR, vincristine; ETO, etoposide; PRD, prednisone.