SOLITARY PLASMACYTOMA OF BONE AND SOFT-TISSUE

Purpose: This retrospective review evaluates the results of radiothera py used for curative intent in the management of solitary plasmacytoma . Methods and Materials: Between August 1963 and January 1993, 37 pati ents with a solitary plasmacytoma were treated with curative intent at the University of Florida. Criteria for inclusion in the study were ( a) a biopsy-proven plasmacytoma, (b) no tumor in the bone marrow on bi opsy, and (c) no evidence of disseminated disease on skeletal survey. The primary site was osseous in 27 patients and extramedullary in 10 p atients; 9 of the 10 extramedullary lesions were located in the upper respiratory passages. Treatment consisted of primary radiotherapy in a ll but one patient, who received surgical resection alone. Two patient s also received adjuvant chemotherapy. The median radiation dose was 4 3.2 Gy in 1.8-Gy fractions. Absolute survival, progression to myeloma, and local control rates were calculated using the Kaplan-Meier method . A multivariate analysis was performed for prognostic factors predict ive of absolute survival. Results: Multivariate analysis revealed tumo r type (osseous vs. extramedullary) to be predictive of absolute survi val (p = 0.12). Factors not predictive of survival were age, sex, use of chemotherapy, immunoglobulin level, and type of immunoglobulin elev ated. Patients with osseous tumors had a lower survival rate than thos e with extramedullary tumors (55% vs. 80% at 10 years, p = 0.06). Mult iple myeloma was more likely to develop in patients with osseous tumor s (54% vs. 11% at 10 years, 100% vs. 33% at 15 years, p = 0.03). Of pa tients in whom multiple myeloma developed, those with osseous tumors h ad a poorer survival rate after development of myeloma (32% vs. 100% a t 5 years, p = 0.11). Local relapse developed in 1 patient with an oss eous tumor 10 months after treatment with 28.3 Gy in 14 fractions; thi s was controlled with an additional 28.3 Gy in 10 fractions. Local fai lure did not develop in any patient with an extramedullary tumor. Conc lusions: Radiotherapy is an effective local treatment for solitary pla smacytoma. Osseous tumors were Pound to have a poor prognosis compared with extramedullary tumors. Copyright (C) 1996 Elsevier Science Inc.