Background: Solitary plasmacytoma (SP) of the bone is a rare plasma-cell neoplasm. There are no conclusive data in the literature on the optimal radiation therapy (RT) dose in SP. Therefore, in this large retrospective study, we wanted to assess the outcome, prognostic factors, and the optimal RT dose in patients with SP.Methods: Data from 206 patients with bone SP without evidence of multiple myeloma (MM) were collected. Histopathological diagnosis was obtained for all patients. The majority (n = 169) of the patients received RT alone; 32 chemotherapy and RT, and 5 surgery. Median follow-up was 54 months (7–245).Results: Five-year overall survival, disease-free survival (DFS), and local control was 70%, 46%, and 88%; respectively. Median time to MM development was 21 months (2–135) with a 5-year probability of 51%. In multivariate analyses, favorable factors were younger age and tumor size < 5 cm for survival; younger age for DFS; anatomic localization (vertebra vs. other) for local control. Older age was the only predictor for MM. There was no dose-response relationship for doses 30 Gy or higher, even for larger tumors.Conclusion: Younger patients, especially those with vertebral localization have the best outcome when treated with moderate-dose RT. Progression to MM remains the main problem. Further investigation should focus on adjuvant chemotherapy and/or novel therapeutic agents.

The aim of this study was to evaluate prognostic factors, survival rate and the efficacy of the treatment modalities used in patients with extraskeletal Ewing's sarcoma. Data of patients with extraskeletal Ewing's sarcoma followed up at our center between 1997 and 2010 were retrospectively analyzed. The median age of 27 patients was 24 years (range, 16–54 years). The median follow-up was 31.8 months (range, 6–144 months). Tumor size was between 1.5 and 14 cm (median: 8 cm). Eighty-five percent of patients had localized disease at presentation and 15% had metastatic disease. Local therapy was surgery alone in 16% of patients, surgery combined with radiotherapy in 42% and radiotherapy alone in 27%. All patients were treated with vincristine, doxorubicin, cyclophosphamide and actinomycin-D, alternating with ifosfamide and etoposide every 3 weeks. In patients with localized disease at presentation, the 5-year event-free survival and overall survival were 59.7 and 64.5%, respectively. At univariate analysis, patients with tumor size ≥8 cm, high serum lactate dehydrogenase, metastasis at presentation, poor histological response to chemotherapy and positive surgical margin had significantly worse event-free survival. The significant predictors of worse overall survival at univariate analysis were tumor size 8≥ cm, high lactate dehydrogenase, metastasis at presentation, poor histological response to chemotherapy, radiotherapy only as local treatment and positive surgical margin. Prognostic factors were similar to primary osseous Ewing's sarcomas. Adequate surgical resection, aggressive chemotherapy (vincristine, doxorubicin, cyclophosphamide and actinomycin-D alternating with ifosfamide and etoposide) and radiotherapy if indicated are the recommended therapy for patients with extraskeletal Ewing's sarcoma.