Primary Bone Lymphomas: Long-Term Results of a Prospective Single-Center Trial

Background. Primary bone lymphomas (PBL) are rare extranodal lymphomas. In more than 90 % of cases they are reported as diffuse large B-cell lymphomas (DLBCL). At local (IE) stage of PBL the standard R-CHOP immunotherapy demonstrates efficacy over 90 %. If, however, such poor prognostic factors (PPF) as multiple bone lesions (IVE stage), increased lactate dehydrogenase (LDH) activity, B-symptoms, and large tumor mass are identified, R-CHOP efficacy tends to decrease. There is currently no optimal regimen for treatment of PBL patients with PPF. We suggest intensified multiagent chemotherapy for this category of patients. Aim. To assess long-term results of prospective single-center trial on the use of high-dose mNHL-BFM-90 program in patients with primary bone DLBCL and PPF. Materials & Methods. The trial included 33 patients with primary bone DLBCL followed-up at the National Medical Hematology Research Center from 2006 to 2018. The median age of patients was 44 years (range 16-78 years). The spectrum of assessed data included main clinical, laboratory, X-ray and MRI tumor characteristics as well as survival rates and prognostic factors. Results. PPF were identified in 29 (88 %) patients, out of them 20 (61 %) patients had an advanced stage (> IE), 20 (59 %) patients showed an increased LDH activity, B-symptoms were identified in 15 (45 %) patients, and large tumor mass was reported in 23 (71 %) patients. High-dose antitumor treatment (mNHL-BFM-90) was administered in 27 out of 33 patients. Overall and progression-free survival within the period of 5 years was 92 %. None of PPF significantly influenced survival rates. Conclusion. The use of high-dose mNHL-BFM-90 program in PBL with poor prognosis achieves long-term remissions in 92 % patients. We recommend mNHL-BFM-90 as a therapy of choice for PBL patients with poor prognosis.