HIGH-DOSE CHEMOTHERAPY FOR PRIMARY DIFFUSE LARGE B-CELL LYMPHOMA OF THE CENTRAL NERVOUS SYSTEM. INTERIM RESULTS OF THE CNS-2015 PROTOCOL

Introduction. Induction chemotherapy (CT) for primary diffuse large B-cell lymphoma (DLBCL) of the central nervous system (CNS) is based on the use of methotrexate in high doses. An optimal consolidation strategy involves high-dose chemotherapy followed by autologous haematopoietic stem cell transplantation (auto-HSCT). The most effective conditioning regimen comprises a combination of chemotherapy agents including thiotepa. Aim. To present the authors’ experience of applying auto-HSCT/TBC in patients with primary DLBCL of the CNS. Methods. The prospective study CNS-2015 was carried out among 20 patients aged 20–52 years (median 42 years old) from 2015 to 2019. The male/female ratio came to 13/7. The somatic status of 17 (85 %) patients was 0–1 on the ECOG scale. Only 3 (15 %) patients showed the somatic status of 4 points. According to the criteria of the MSKCC prognostic system, 18 (90 %) and 2 (10 %) patients were assigned to the low-risk and medium-risk groups, respectively. Results. All patients included in the study received 3–5 cycles of chemotherapy with high doses of methotrexate, vincristine, procarbazine and rituximab (R-MPV), as well as underwent auto-HSCT following TBC-based conditioning regimen (thiotepa, busulfan, cyclophosphamide). Prior to auto-HSCT, 15 and 5 out of 20 patients having completed induction chemotherapy achieved complete remission and partial remission, respectively. Following auto-HSCT, complete remission was achieved in 5 patients with an initial partial response to treatment. All patients underwent temozolomide maintenance therapy for 2 years. With a median follow-up of 17 (1–46) months, 18 patients are alive and in remission. Two patients, who relapsed 4 and 5 months after auto-HSCT and achieved no response to the second line of chemotherapy and radiation therapy, died 24 and 26 months after auto-HSCT. Conclusion. R-MPV is an effective treatment for patients with primary DLBCL of CNS, which is not accompanied by severe toxicity. The use of high-dose chemotherapy with TBC allows a high remission rate to be achieved. The mortality associated with treatment in the group of patients included in the study came to 0 %.