The purpose of JCOG9809 was to determine whether treatment results of aggressive NHL could be improved by shortening intervals of CHOP chemotherapy with the prophylactic use of G-CSF. The primary endpoint was Progression Free Survival (PFS), and the planned accrual was 450. Until December, 2002, 323 patients with advanced aggressive NHL were randomized to standard CHOP arm (CHOP x 8, every three weeks) and biweekly CHOP arm (CHOP x 8, every two weeks).