Treatment Outcomes in Primary Mediastinal Large B-Cell Lymphoma. Experience of the AF Tsyb Medical Radiological Research Center (Obninsk)

Abstract

AIM. To assess chemotherapy outcomes in patients with primary mediastinal large B-cell lymphoma (PMBCL) treated at the AF Tsyb Medical Radiological Research Center from 2016 to 2023. MATERIALS & METHODS. The analysis focused on the data from 58 patients with the morphologically verified diagnosis of PMBCL. The patients were aged 17–62 years (median 34 years), there were 39 women and 19 men. The median follow-up was 51.2 months (range 0.4–200.9 months). Depending on drug chemotherapy regimens, patients were divided into 3 groups: R-NHL-BFM-90 (n = 9), R-CHOP (n = 17), and R-MACOP-B (n = 32). Most patients (90 %) received mediastinal radiotherapy of total 30–46 Gy. RESULTS. The 5-year overall survival in the therapy groups was 66.7 %, 88.2 %, and 100 %, respectively (p = 0.007), progression-free survival was 66.7 %, 70.6 %, and 96.9 % (p = 0.006), and event-free survival was 66.7 %, 54.7 %, and 90.6 % (p = 0.038). On the whole, the toxicity profile of chemotherapy was quite acceptable. Neither low blood values nor other adverse events essentially affected a complete implementation of chemoradiotherapy program. The intermediate outcomes were based on PET-CT data after 2–4 therapy cycles in 37 (64 %) patients. PET-CT showed that at the stage of drug chemotherapy, complete response (CR) was achieved in 27 (73 %) patients, and partial response (PR) was achieved in 4 (11 %) patients. With respect to the CR and PR criteria, there were 6 (16 %) non-responders. CONCLUSION. PMBCL is one of extranodal lymphomas with thymic B-cells being primary source of tumor growth. PMBCL is characterized by aggressive course and extreme heterogeneity of clinical manifestations. Up to now, the first-line chemotherapy decision making in PMBCL has remained an issue with practical importance. This paper reports immediate and long-term outcomes of the program chemoradiotherapy regimen R-MACOP-B with subsequent consolidation radiotherapy. The results obtained can be termed quite satisfactory and noninferior to the data from national and international sources. Nevertheless, more effective chemoradiotherapy programs for PMBCL continue to be elaborated. In this context, immune checkpoint inhibitors as part of therapy programs seem to hold promise for the treatment of newly diagnosed PMBCL.