Chemotherapy
In the decitabine‐RDHAP group, decitabine was administered intravenously for 5 days at 10 mg/day, followed by a modified DHAP regimen. The DHAP regimen was modified because the enrolled patients were almost all in the advanced stage and bone marrow ability of patients was poor. The following RDHAP regimen was administered. Rituximab was then administered intravenously at 375 mg/m