Impact Of Sex On Clinical Outcomes Of Mature B Cell Lymphoma In The Rituximab Era: A Multicenter, Retrospective Study

Rituximab has dramatically improved the clinical outcomes of mature B cell lymphoma. It has been reported that women show more favorable survival than men with rituximab-containing treatment. A multicenter, retrospective study was conducted to assess the role of sex in survival with rituximab treatment.

Patients with newly diagnosed mature B cell lymphoma treated at 20 National Hospital Organization hospitals in Japan from January 2000 to December 2004 were consecutively registered. Rituximab was approved in September 2002 for indolent B cell lymphoma and in September 2003 for aggressive B cell lymphoma in Japan. The patients were divided into two groups depending on whether they received induction therapy containing rituximab. The target population of this study was all mature B cell lymphoma patients who received first remission induction therapy containing rituximab. The patients treated without rituximab were used as controls. The endpoint was to compare 2-year progression-free survival (PFS) and overall survival (OS) between men and women. Survivals were assessed using the Kaplan-Meier method, and the groups were compared using the log-rank test.

A total of 1126 patients received systemic chemotherapies during this study period. Of these, 348 (men 185, women 163), including 184 diffuse large B cell lymphomas (DLBCLs) and 111 follicular lymphomas (FLs), were treated by rituximab-containing regimens as front-line therapy. The 2-year PFS was better in women than in men (75.8% vs. 64.2%, p=0.048). This difference was not seen in the control group (men 396, women 382), which was treated by chemotherapeutic regimens without rituximab (48.7% vs. 50.6%, p=0.994). The 2-year OS was not statistically different between men and women (81.9% vs. 88.6%, p=0.115). When this population was broken down into DLBCL and FL, the women’s benefit in 2 year PFS was not statistically significant in both subtypes. Multivariate analysis both with forced entry and stepwise method could not show that sex was an independent prognostic factor in mature B cell lymphoma treated by rituximab containing induction regimen.

In mature B cell lymphoma, women would have better PFS than men when treated with rituximab containing therapy. These data suggest that the sex-based rituximab dose modification might be considered.

No relevant conflicts of interest to declare.