SOLITARY PLASMOCYTOMA: 19-YEAR RETROSPECTIVE STUDY AND REVIEW OF THE LITERATURE

Solitary Plasmacytoma (SP) is a rare plasma cell dyscrasia characterized by localized plasma cell infiltration. Radiotherapy is recommended as the treatment of choice. Epidemiological data is important to evaluate the effectiveness of treatment and the progression to Multiple Myeloma (MM). We described the clinical features and follow-up of 32 patients with SP treated with radiotherapy as primary treatment at our Department of Radiotherapy and we reviewed the literature on prognostic factors of progression to MM. Ninety percent of patients (71% complete response and 19% partial response) responded to treatment. Fourteen patients progressed to MM with a median time of progression of 16, 9 months. With a median follow-up of 40 months, the 5 and 10-year estimated Overall Survey (OS) was 62, 6% and 47, 7% respectively. Predictive factors of progression are still controversial. New factors are emerging in the fields of pathology, imagiology and immunology and thus we wait longer follow-up to confirm their predictive value. SP is highly radiosensitive and radiotherapy combines excellent control rates with minimal toxicity. However, it is a heterogeneous disease and approximately half of the patients will progress to MM. Identifying the patients more likely to progress would allow us to treat them in a different way.