Primary Bone Lymphoma: An Experience of a Regional Cancer Center from India.

Background  Primary bone lymphoma (PBL) is a rare disease, representing <5% of all extranodal non-Hodgkin's lymphomas (NHLs). The optimal treatment strategy is still unclear. Here, we report our institutional outcome analysis of patients diagnosed with PBL. Materials and Methods  From 2007 to 2014, the medical records of 22 patients with PBL were reviewed. Analysis was done for symptom-, patient-, disease-, and treatment-related characteristics. All patients were treated with chemotherapy with or without radiotherapy. Treatment response and impact of different prognostic factors on clinical outcome were analyzed. Results  The median age of presentation was 44 years (range: 18-70 years). A total of 19 (86.4%) patients were ≤60 years of age and 3 (13.6%) patients were >60 years. Out of all, 18 were males and 4 were females. Ann Arbor clinical staging at diagnosis was Stage I in 13 (59.1%), Stage II in 3 (13.6%), Stage III in 2 (9.1%), and Stage IV in 4 (18.2%) patients. Spine was the most common site of involvement seen in 12 (54.5%) patients. Diffuse large B cell lymphoma histology was seen in 8 (36.4%) patients and 8 (36.4%) had high-grade NHL. Chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone was given to 20 (90.9%) patients, whereas 2 (9.1%) patients received cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab. Radiotherapy (30-40 Gy) was delivered to 19 (86.4%) patients. The median follow-up period was 40 months (range: 8-105 months). The overall response rate was 86.3% with complete response (CR) in 15 (68.1%) and partial response in 4 (18.2%) patients. Relapses were seen in three (13.5%) patients: two nodal, and one in the bone. Disease-free survival (DFS) and overall survival (OS) at 5 years were 56.6 and 72.7%, respectively. CR after initial treatment was associated with a significant better OS, 80 and 25%, respectively ( p < 0.0001). Age, sex, stage, International Prognostic Index, histologic subtype, and number of sites had no significant influence on OS. Combining radiation therapy with chemotherapy (with or without rituximab) also did not improve the OS or DFS of patients. Conclusion  In spite of small number of patients reported in this study, conventional chemotherapy remains an effective treatment option for patients with PBL. OS was found to be affected by the initial response to treatment.