Extramedullary plasmacytoma: clinical behaviour and response to treatment

The clinical features and response to treatment of 35 patients (pts) with extramedullary plasmacytoma (EMP) were retrospectively analysed. The median age at diagnosis was 49 years (28-72). Twenty-two pts (63%) had stage I disease (localized to the primary site) 12 of whom (34%) had stage I-E (locally extended). Three pts (9%) had stage II (regional lymph nodes involved) and 10 (29%) stage III (disseminated disease). In locoregional disease (stages I, I-E, II) complete local control was achieved in 22 of 25 pts (88%), while in diffuse disease (stage III) complete remission (CR) was obtained in 5 of 10 pts (50%) (p = 0.05). In 9 of 18 pts treated with surgery, local control was achieved, and in 8 of the 9 patients with incomplete resection local control was obtained with additional radiation and/or chemotherapy. In 8 (66%) of the 12 pts treated with radiation complete local control was achieved. In 11 (58%) of 19 pts evaluable for initial chemotherapy CR was obtained. Three of these pts were treated with chemotherapy only and were alive and disease-free after a minimum follow-up of 8 years. The median time to relapse in local disease was 48 months versus 13 in disseminated disease. For pts with local disease the median survival time was 114 months and for disseminated disease 16 months (p = 0.0000). We conclude that in stage I chemotherapy is curative per se. In local stages (I, I-E and II) adjuvant chemotherapy should be considered, while in stage III only palliative therapy is feasible.