Rituximab in combination with CHOP chemotherapy for the treatment of diffuse large B cell lymphoma in Japan: a retrospective analysis of 1,057 cases from Kyushu Lymphoma Study Group.

We performed a retrospective analysis of patients with diffuse large B cell lymphoma treated with rituximab plus CHOP (cyclophosphamide, adriamycin, vincristine and prednisone) as a first-line therapy at 22 hospitals of the Kyushu Lymphoma Study Group. During the period 1996-2005, 1,057 patients (aged 22-90 years) were analyzed. Of these, 678 were treated with CHOP, and 379 were treated with rituximab plus CHOP (R-CHOP). The complete response rate was 59.9% in the CHOP group and 67.0% in the R-CHOP group (P < 0.001). Three-year progression-free survival (PFS) and overall survival (OS) rates were significantly higher in the R-CHOP group than in the CHOP group (61.3 vs. 45.6% for PFS, P < 0.001; 68.3 vs. 54.5% for OS, P < 0.001). The International Prognostic Index was a good prognostic marker for both groups; a survival benefit of rituximab addition was found for each risk subgroup and also for both age groups (60 years). Among 345 patients who received localized radiation therapy, the adding rituximab to CHOP attenuated the survival difference between CHOP and R-CHOP groups (P = 0.104), compared with no radiation group (P < 0.001). Results of this large-scale, multicenter study confirm that rituximab plus CHOP provided a greater survival benefit than CHOP alone.