Impact of relative dose intensity (RDI) in CHOP combined with rituximab (R-CHOP) on survival in diffuse large B-cell lymphoma

BACKGROUND Recently, maintaining higher relative dose intensity (RDI) of chemotherapeutic drugs has become a widespread practice in an attempt to achieve better outcomes in the treatment of aggressive lymphoma. The addition of rituximab to chemotherapy regimens has significantly improved outcome in diffuse large B-cell lymphoma (DLBL). However, it is unknown if higher RDI in chemotherapy when combined with rituximab leads to a better outcome in aggressive B-cell lymphoma. METHODS We retrospectively evaluated the impact of the RDI of initial chemotherapy (consisting of cyclophosphamide, doxorubicin, vincristine and prednisolone with rituximab (R-CHOP) on outcome in 100 newly diagnosed DLBL patients. RESULTS A multivariate Cox regression model showed that RDI trended towards a significant association with mortality [hazard ratio per 0.1 of RDI = 0.8; 95% confidence interval 0.6-1.0; P = 0.08]. Additionally, on multivariate logistic analysis, advanced age was a significant factor for reduced RDI. CONCLUSION Our data suggest that in DLBL patients, mortality was affected by RDI of R-CHOP as the initial treatment, and the retention of a high RDI could therefore be crucial.