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.