Effect of response quality and line of treatment with rituximab on overall and disease-free survival of patients with B-cell lymphoma

Background. The introduction of rituximab into the treatment of patients with non-Hodgkin's lymphomas has improved the overall response rate, as well as the response duration and the overall survival of patients with B-cell lymphomas. But only a few studies have addressed the question whether the better response (complete response) and the early introduction of rituximab into the treatment translate into the better survival. The aim of this retrospective study was to assess the potential relationship between either the quality of the response or the line of the rituximab treatment and the overall survival (OS) as well as the disease-free survival (DFS) of patients with B-cell lymphomas. Patients and methods. In the study, we analysed treatment outcomes in patients with different histological types of B-cell lymphomas who were treated at the Institute of Oncology between 2003 and 2007 with rituximab and chemotherapy. We included only patients who had the level of CD20 expression assessed prior to the introduction of the treatment with quantitative flow-cytometric measurements. The OS and DFS were evaluated by Kaplan-Meier survival curves. Results. One hundred and fourteen patients were enrolled in the study. Patients who achieved a complete response after the rituximab containing treatment had a significantly longer OS than those reaching a partial response (hazard ratio [HR], 0.34; 95% CI, 0.05 to 0.91, P = 0.0375) and than patients with stable (hazard ratio [HR], 0.11; 95% CI, 0.0002 to 0.033, P < 0.0001) or progressive disease (hazard ratio [HR], 0.09; 95% CI, 0.003 to 0.03, P < 0.0001). Patients who achieved a complete response (CR; n = 70; 61.4%) had also a significantly longer DFS (hazard ratio [HR], 0.26; 95% CI, 0.021 to 0.538, P = 0.0068) than those reaching only a partial response (PR; n = 17; 14.9%). Patients treated with rituximab as the first-line treatment (n = 50; 43.9%) had a significantly longer OS than those treated with rituximab for the first (hazard ratio [HR], 0.27; 95% CI, 0.106 to 0.645, P = 0.0036) or second relapse (hazard ratio [HR], 0.22; 95% CI, 0.078 to 0.5, P = 0.0006). Also the DFS of patients treated with rituximab as the first-line treatment (n = 46; 52.9%) was significantly longer (hazard ratio [HR], 0.32; 95% CI, 0.088 to 0.9, P = 0.0325) than in patients treated with rituximab for their first relapse (n = 25; 28.7%). Conclusions. These data indicate that a better response to rituximab therapy presumably translates into an improved OS and DFS for patients with B-cell lymphomas. The early introduction of rituximab into the treatment (i.e. first-line treatment) might improve OS. Therefore, the response adapted first-line therapy with rituximab should be considered when the treatment decision is taken in B-cell lymphoma patients.