Primary Bone Lymphoma: A 13 Year Retrospective Institutional Analysis in the Chemo-Immunotherapy Era.

Primary Lymphoma of bone (PBL) is an uncommon extranodal tumor accounting for 1% of all malignant lymphomas. The incidence of PBL is so rare that many of its aspects remain unknown. We retrospectively analysed our data in order to know clinical characteristics and treatment outcome in Indian population in chemo-immunotherapy era. We identified 49 patients [2007-2019] (median age 52 years) of which, 35 (71.4%) were males. Nearly one-third patients (n = 18; 36.8%) were elderly (Age > 60). The most common histological subtype was DLBCL. Local pain /swelling (n = 23; 47%) and B symptoms (n = 20; 44.4%) was the most common presentation. Spine was the most frequently involved site (n = 25; 51%) followed by pelvis (n = 17; 34.7%). One third patients had poor ECOG-PS ≥ 2, (n = 16; 32.6). More than 50% of the population presented with IPI score ≥ 2 (n = 25; 55.5%). Majority of the patients presented with Ann-Arbor stage IV disease (n = 31; 63.2%). (n = 32; 71.1%) cases received chemotherapy alone and (n = 13; 28.9%) patients were treated in combination with local radiotherapy. R-CHOP was the most common treatment regimen given to patients (n = 43; 95.5%). Overall, three-fourth patients (n = 36; 80%) achieved a complete response. At a median follow-up of 45 ± 2 (range 3-144) months, 4-year OS (Overall Survival) and PFS (Progression free survival) was 83.1% and 74.5%, respectively, using Kaplan-Meier survival curves. Prognostic factors for OS on multivariate analysis were ECOG-PS 0-1 [p = 0.05], age < 60 [p = 0.03] and achievement of CR [p = 0.001]. PBL in India is usually of DLBCL subtype, with spine as the most common site. It has an excellent prognosis in the R-CHOP era. Chemo-immunotherapy with 6 R-CHOP followed by addition of Radiotherapy if partial response appears to provide good outcomes. However, the exact role of radiation still needs to be confirmed.