Clinical characterization and prognostic factors of primary lymphoma of bone in case of Chinese patients.

Primary lymphoma of bone (PLB) is a very rare neoplasm. Many aspects of this entity have not been well defined or reported in Chinese population. The purpose of our study is to identify the prognostic factors of PLB. Twenty-five patients newly diagnosed with PLB were included in this retrospective study. The main pathologic subtype of PLB was diffuse large B-cell lymphoma (DLBCL), followed by anaplastic large-cell lymphoma. The pelvis was the most commonly involved site (13 cases, 52%). The 5-year overall survival (OS) rate was 55.0%. Cox regression analysis demonstrated that IPI score was an independent prognostic factor of survival (RR = 8.46, P = 0.013). The mean survival time (MST) was 90.3 months for patients with radiation and 54.0 months for those without radiotherapy (P = 0.033). Patients who received the anti-CD20 monoclonal antibody rituximab therapy showed a favorable survival trend, but not significant benefit (MST: 74.5 months vs. 68.6 months, P = 0.149). Some clinical characteristics in the Chinese population are different from those in westerners. The frequency of T-cell subtypes is higher, and the pelvis is the most commonly involved site. Irradiation plus chemotherapy may be better than chemotherapy alone. The role of bisphosphonates and rituximab in PLB therapy warrants further investigation.