Addition of Rituximab to CHOP Chemotherapy Does Not Improve Clinical Outcome in Patients with Localized Gastric Diffuse Large B-Cell Lymphoma: A Retrospective Study by Ganken Adult Lymphoma Study Group (Single Institute Analysis).

Background: In recent years, it has been reported that addition of rituximab to CHOP chemotherapy significantly improves event-free survival (EFS) and overall survival (OS) compared with standard CHOP alone in patients with diffuse large B-cell lymphoma (DLBCL). On the other hand, gastric DLBCL is a good clinical outcome without surgical excision in the group of primary extranodal DLBCL. Localized gastric DLBCL shows very good EFS and OS treated with standard CHOP plus radiation therapy without rituximab.

Methods: We analyzed retrospectively the prognosis between R-CHOP and CHOP alone in patients with localized gastric DLBCL. All 24 patients diagnosed between July 1999 and July 2006 in our hospital, were included in this study. The pathology was reviewed by a hematopathologist and confirmed to be de novo DLBCL according to the WHO classification. The staging system was using by Lugano meeting classification. Patients with stage IIE and IV were excluded. All patients were initially treated with six cycles of CHOP or R-CHOP regimen consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone. If we evaluated partial response after six cycles of chemothrapy, the patients have been added radiation therapy.

Results: Initial characteristics of the 24 patients are summarized in Table 1. The median age of patients at time of inclusion was 67.5 yr (range 30–83 yr). The median follow up of surviving patients was 30 months. CR rates between CHOP and R-CHOP were 91.7% vs. 83.3%, p=1.000, and overall response rates were 100% vs. 83.3%, p=.478, respectively. 2 years progression-free survival and overall survival were no statistical significance difference between two groups (Log rank test: P=.138, P=.739).

Conclusion: These results suggested that addition of rituximab to CHOP chemotherapy does not improve clinical outcome of localized gastric DLBCL. The patients with localized gastric DLBCL did not get the clinical benefits of rituximab. As you know, rituximab needs high costs, so we recommend standard CHOP regimen plus radiation therapy in patients with localized gastric DLBCL, without rituximab combination regimen.