Clinical Characteristics and Prognostic Factors of Primary Bone Diffuse Large B-Cell Lymphoma: A Retrospective Study.

BACKGROUND: Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is a rare extranodal lymphoma with heterogeneous clinical features and survival outcomes. Although most patients respond favorably to modern immunochemotherapy, reliable baseline prognostic indicators remain insufficiently defined. METHODS: We retrospectively analyzed 424 patients with histologically confirmed PB-DLBCL. Clinical characteristics, treatment patterns and survival outcomes were evaluated. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method. Prognostic factors were assessed by univariate and multivariate Cox regression analyses. RESULTS: With a median follow-up of 36 months, the 3 year OS and PFS rates were 81.3% and 63.3%, respectively. In multivariate analysis, high-risk International Prognostic Index (IPI; score 3-5) was independently associated with inferior OS (HR 2.06, 95% CI 1.24-3.43, p = 0.006). For PFS, hypoalbuminemia (< 40 g/L) emerged as an independent predictor (HR 1.44, 95% CI 1.03-2.02, p = 0.035). Although failure to achieve complete remission and high Deauville score were associated with worse outcomes in univariate analyses, these post-treatment variables were not included in multivariable models. CONCLUSION: PB-DLBCL often presents with advanced disease but demonstrates generally favorable survival in the rituximab era. Baseline IPI remains a robust predictor of OS, while hypoalbuminemia independently predicts disease progression.