LAUSR

e19539 Background: Diffuse large B-cell lymphoma (DLBCL) is and aggressive heterogeneous tumor. The treatment is ineffective in more than 30% cases: primary resistance is observed in 20%, and relapses in 10%. Clinical prognostic indices do not allow assessing the DLBCL course and treatment outcomes. The purpose of the study was to evaluate the results of treatment of DLBCL patients depending on clinical and immunohistochemical factors of the disease prognosis. Methods: Patients with DLBCL (n = 48): men – 25 (52.1%, mean age 52±3.8 years), women – 23 (47.9%, mean age 60±4.3 years) received standard treatment R-CHOP, R-CHOEP, R-EPOCH. Results: After the treatment, 27 (56.2%) patients were in remission for 3 years, 10 (20.8%) patients developed relapses, and 11 (23%) patients were refractory to the therapy. All groups demonstrated Ki-67 > 80%, overexpression of Bcl2, Bcl6, CD10, MUM-1 on tumor cells, C-MYC gene rearrangements. Patients with stage I and II nodal spread were more likely to be in remission; refractory patients and those with early relapses had stages III and IV. Relapses were detected at different periods after treatment: early relapses (n = 5) within 6 months and late relapses (n = 5) after 12 months or later. Among patients with early relapses, 2 (40%) had extranodal disease and 3 (60%) nodal disease; high/medium IPI was noted in 3 patients, low/medium and low IPI – 1 patient each. Among patients with late relapses, 3 patients had nodal disease and 2 – primary extranodal disease; high/medium IPI was noted in 2 patients, low/medium – in 3 patients. Among recurrent patients, 9 had non-germ cell DLBCL and 1 - germ cell DLBCL. Among refractory patients, 8 (73%) had nodal disease and 3 (27%) - extranodal disease; low/medium IPI was registered in 4 patients, high/medium IPI in 2, low IPI in 5 patients; germ cell tumors in 2 patients, non-germ cell tumors in 9 patients. Conclusions: 33% of DLBCL patients did not benefit from the treatment. Molecular markers such as Ki-67, Bcl2, Bcl6 and CD10 were not prognostically significant. The tumor type had a prognostic value only in the group of patients with relapses - non-germ cell tumors were found in 90% of cases.