Prognostic Factors and Treatment Efficacy in Patients with Primary Diffuse Large B-cell Lymphoma of the Bone: Single Institute Experience Over 11 Years

Objective Primary bone lymphoma is a rare disorder, accounting for less than 1% of all cases of malignant lymphoma. Primary bony diffuse large B-cell lymphoma (PBDLBCL) is the most common histological type. In our study, a favorable response and lower risk of emergent surgery were observed following the administration of systemic chemotherapy with or without rituximab. Methods Patients diagnosed with malignant lymphoma at our hospital between 2000 and 2011 were evaluated for PBDLBCL. Pertinent data, including the clinical presentation, histological type, treatment modalities, long-term outcome, survival curve and prognostic factors, were analyzed. Results Twenty-four patients with a median age of 63 years were diagnosed with PBDLBCL. A complete response (CR) was achieved in 58.4% (n=14) of the patients. With treatment of the disease, nine of 10 patients with initially impending pathological bone fractures ultimately did not undergo surgery. The median follow-up duration was 48 months. Two patients experienced disease relapse. In a Kaplan-Meier analysis, the 5-year overall survival (OS) and disease-free survival (DFS) rates were 66.7% and 77.8%, respectively. In the univariate analyses, the significantly favorable prognostic factors for OS were an International Prognostic Index (IPI) score of <3, an age of <= 60 years, a performance status with an Eastern Cooperative Oncology (ECOG) score of <2, a CR and chemotherapy >= 6 cycles. For DFS, a CR was the only favorable factor. In the multivariate analysis, a CR was the only independent factor for both OS and DFS. Conclusion Our study confirms the good prognosis of this rare disorder. Once a CR is achieved, even elderly patients may exhibit long-term survival, possibly obviating the need for surgery for less severe bone lesions.