Extramedullary plasmacytoma: tumor occurrence and therapeutic concepts

Extramedullary plasmacytoma (EMP) is a rare entity belonging to the category of non-Hodgkin lymphoma. EMPs make up 4% of all plasma cell tumors and occur mainly in the upper aerodigestive tract (UAD). Seven patients with EMP included in this evaluation were under the authors' care and have been clinically followed since 1990. Because there are no general guidelines for the treatment of patients with EMP, the authors tried to obtain detailed data about the occurrence of this disease and also reviewed the therapies that have been used. To do so, they evaluated all EMP cases published in the medical literature until now and included their own experience.

Based on the clinical course and follow-up of their own EMP patients, the authors evaluated and reinvestigated all EMP cases cited in MEDLINE, Index Medicus, DIMDI (Deutsches Institut fur medizinische Dokumentation und Information, Cologne, Germany), and the reference lists of the publications found through these sources.

In a detailed literature search, more than 400 publications between 1905 and 1997 were found, and these revealed that EMP mainly occurs between the fourth and seventh decades of life. Seven hundred fourteen cases (82.2%) were found in the UAD, and 155 cases (17.8%) were found in other body regions. The following therapeutic strategies were used to treat patients with EMP of the UAD: radiation therapy alone in 44.3%, combined therapy (surgery and radiation) in 26.9%, and surgery alone in 21.9%. The median overall survival or recurrence free survival was longer than 300 months for patients who underwent combined intervention (surgery and radiation). This result was statistically highly significant (P = 0.0027, log rank test) compared with the results for patients who underwent surgical intervention alone (median survival time, 156 months) or radiation therapy alone (median survival time, 144 months). In most cases of non-UAD EMP, surgery was performed (surgery alone, 55.6%; surgery and radiation combined, 19.8%; radiation alone, 11.1%), but there were no statistical differences in survival (P = 0.62). Overall, after treatment for EMP in the UAD, 61.1% of all patients had no recurrence or conversion to systemic involvement (i.e., multiple myeloma, MM); however, 22.0% had recurrence of EMP, and 16.1% had conversion to MM. After treatment for EMP in non-UAD areas, 64.7% of all patients had no recurrence or MM, 21.2% had recurrence, and 14.1% had conversion to MM.

The current investigation provides evidence that surgery alone gives the best results in cases of EMP of the UAD when resectability is good. However, if complete surgical tumor resection is doubtful or impossible and/or if lymph node areas are affected, then combined therapy (surgery and radiation) is recommended. These results, which were obtained from retrospective studies, should be confirmed in randomized trials comparing surgery with combined radiation therapy and surgery.