Clinical and Prognostic Features of Plasmacytoma: Outcome Analysis of 29 Cases in SNUH

Abstract

Purpose/Objective(s): To examine the clinical features and to identify the outcomes of prognostic factors of solitary plasmacytoma (SP). Materials/Methods: The data from 29 patients with solitary plasmacytoma (SP) diagnosed in Seoul National University Hospital from 1986 to 2008 was collected. The median age was 60 years old with the range of 30 through 76, and the ratio of male to female was 1.9:1. Among 29 patients, 22 were solitary plasmacytoma of bone (SPB), and 7 were extramedullary plasmacytoma (EMP). The therapies that the patients received were: radiotherapy (RT) alone (n = 15), surgery and radiotherapy (n = 9), surgery alone (n = 4), and chemotherapy alone (n = 1). The median radiation dose was 4460 cGy (range, 2340-5600). The median follow-up was 3.7 years (range, 0.8 -14.11). Results: The 5-year overall survival (OS) rate was 60%; the 5-year progression free survival (PFS) rate was 57%; the 5-year local control (LC) rate was 96%; the 5-year multiple myeloma free (MMF) rate was 68%. The common sites of SPB included vertebral bodies (n = 12), and pelvic bone (n = 4). Most EMPs occurred in the oronasopharynx (n = 4). Only one local failure occurred 14 months after surgery alone in the SPB group. Other patterns of failure in the 22 patients with SPB manifested as distant relapse in three (median times: 18.5 month), and progression to multiple myeloma (MM) in six (median time: 17 month). There were two progressions to other diseases in the SPB group. One patient was diagnosed renal amyloidosis at 47 months and the other patient developed POEMS (Polyneuropathy, Organomegaly, Endocrinopathy,Mprotein, and Skin changes) syndrome at 35 months from the date of primary diagnosis. Among patients with EMP, there was only one progression to MM at 24 months from the date of primary diagnosis. On univariate analyses, younger age (\60 year) was a favorable factor for OS. RT modality (RT alone, surgery and RT) was a favorable factor for the LC rate. Localization (SPB vs. EMP) was not statistically significant for all outcomes. In terms of RT dose, there was no dose-response relationship for all outcomes. Conclusions: Solitary plasmacytoma presents excellent local control rates. However, progression to MM remains the main problem. For local control, surgery alone is not sufficient. The development of other diseases related to plasmacytoma occurred later than other failures. Therefore, we suggest that long-term follow-up is necessary.