Primary non-Hodgkin's lymphoma of the bone: treatment and analysis of prognostic factors for Stage I and Stage II.

PURPOSE: Primary non-Hodgkin's lymphomas of the bone (PLB) are very rare diseases accounting for 3%-5% of primary bone tumors. The best treatment for PLB has not been found yet. We report on the experience of the Radiation Oncology Department of Bologna University, Italy, relative to the diagnosis and treatment of this disease.

METHODS AND MATERIAL: Seventy-seven patients with newly diagnosed PLB were treated from June 1983 to October 2001. Fifty-six were male (72.7%) and 21 were female (27.3%); the median age was 41.8 years, with a range of 16-84 years. The majority of patients had B-cell high-grade histology. The median follow-up was 149 months. Forty-four patients had a solitary bone lesion (Stage I); and in 33 patients, the tumor was spread to locoregional lymphatic area (Stage II). All patients were treated with radiotherapy (RT) with a median dose of 40 Gy (range, 36-54 Gy), and 67 received an additional anthracycline-based regimen of chemotherapy (combined modality therapy [CMT]).

RESULTS: After therapy 73 of 77 patients (94.8%) reached a complete remission. At a median time of 23 months, 14 of 77 patients (18.2%) had a disease relapse. Four of them were treated with RT alone (in these cases tumor lesions were <3 cm and located at sites different from mandible); 10 patients were treated with combined RT and CMT. Actuarial disease-free survival (DFS) and overall survival (OS) at 15 years were, respectively, 76.6% and 88.3%. No local failures were seen. Prognostic factors such as age, sex, stage, and bulky lesions were analyzed. Age (<40 vs. >40 years) was the only significant factor for DFS (85.3% vs. 66.6%, p = 0.03). Bulky lesions apparently did not affect OS (90.9% vs. 72.7%). However, the difference has no statistical significance (p = 0.05). Acute and late toxicity related to the treatment was moderate.

CONCLUSIONS: In PLB the CMT seems to produce a better outcome than RT alone; that still remains the best treatment for local disease control. Radiation therapy alone should be reserved for mandibular tumors, which are usually very small and earlier diagnosed.