Patients receive induction chemotherapy comprising the CHOP or VAPEC-B regimen. The CHOP regimen consists of vincristine (VCR) IV, cyclophosphamide (CTX) IV, and doxorubicin (DOX) IV on day 1 and oral prednisolone (PRDL) on days 1-5. Treatment repeats every 3 weeks for six courses. The VAPEC-B regimen consists of DOX IV on days 1, 15, 29, 43, 57, and 71; CTX IV on days 1, 29, and 57; VCR IV on days 8, 22, 36, 50, and 64; bleomycin IV on days 8, 36, 64; oral etoposide (VP-16) on days 15-19, 43-47, and 71-75; and oral PRDL daily for 13 weeks.