Treatment of NonHodgkin’s lymphomas with rituximab in Slovene patients

The introduction of rituximab into the treatment of patients with NonHodgkin’s lymphomas has changed the long-term prognosis of patients with CD20 positive B cell lymphomas, especially follicular and diffuse large B-cell lymphomas (DLBCLs). The addition of rituximab to chemotherapy improves the overall response rate, prolongs the response duration and the overall survival both in patients with follicular and other indolent CD20 positive lymphomas, and DLBCLs. Maintenance treatment with rituximab in patients with indolent lymphomas further prolongs the remission duration, and some of the studies have also shown survival benefit. However, the maintenance therapy in aggressive lymphomas most probably gives no further improvement in patients, who have received rituximab already in the induction treatment. Rituximab has been used at the Institute of Oncology Ljubljana since 1998. In the period from 2004 to 2006, we have treated 340 patients with rituximab either as a single agent or in combination with chemotherapy. Our treatment group included 46.8% of patients with DLBCLs and 19.4% with follicular lymphomas. In majority of the patients, rituximab was given as the first-line treatment (54.4%), while 26.2% of patients received it as the second-line treatment and 19.4% of patients as the third or subsequent line of treatment. Among patients with indolent lymphomas, just 15% received rituximab as the first-line treatment. On the other hand, 75.9% of patients with aggressive lymphomas were treated with rituximab for newly diagnosed disease. About 67.4% of patients were treated with R–CHOP combination, while the others received different rituximab–chemotherapy combinations. The overall response rate regardless of the histological type of lymphoma was 78.8%, and the highest response rate was achieved in patients with aggressive follicular lymphomas (91.7%). The highest overall response rate was observed when rituximab was given as the first-line treatment in all lymphoma types except the mantle cell lymphoma (66.6% overall response rate for the first-line treatment versus 73.7% overall response rate for the second-line treatment). In 75% of patients regardless of the histological type of lymphoma, the response lasted more than 12 months; the median response duration has not been reached yet. In patients receiving rituximab as the first-line treatment, the median response duration also has not been reached yet, while for the second-line treatment, it was 25 months and for the third or subsequent line, 24 months. The longest disease-free survival was observed in patients with DLBCLs. The overall survival rate of all patients regardless of the type of lymphoma was 75% 26 months after the beginning of the treatment, and the median overall survival has not been reached yet. When analyzed by the lines of treatment—the median overall survival has not been reached in any line. The longest overall survival was observed in patients with indolent follicular lymphomas. The treatment results with rituximab at the Institute of Oncology Ljubljana are comparable to the results of larger randomized trials. According to the beneficial influence of rituximab on the long-term prognosis of patients with CD20 positive lymphomas, it became the standard of treatment in these patients.