O2-4-2 - Clinical Courses of 133 Mgus and 73 Smoldering Multiple Myeloma Registered in Kansai Myeloma Forum

Abstract

Introduction: It is reported that the risks of evolution to the symptomatic multiple myeloma (MM) are 1% per year from MGUS, and 10% during the first five years from smoldering MM (sMM). We have founded the study group (Kansai Myeloma Forum: KMF) for the purpose of registering the patients with MM-related diseases in Kansai area. In this study, the clinical courses of MGUS and sMM among the registered patients were analyzed.Patients and methods: Among the cases registered to KMF, 133 patients with MGUS and 73 with sMM, diagnosed after 2006, were analyzed.Results: In 133 MGUS cases, the median age was 68.0, 73 were males, IgG and IgA types comprised 76.6% and 14.8%, respectively. In the median follow-up period of 2.2 years, 10 patients (6.5%) received chemotherapies because of the disease evolutions. The evolution rates were 1.1% at 1yr, 8.1% at 3yr and 11.1% at 5yr (0.84% per year). The 3-yr OS after the start of treatments was 71.4%. In 73 sMM cases, the median age was 67, 34 were males, IgG and IgA types comprised 75.3% and 17.8%, respectively. In the median follow-up period of 1.1 years, 26 patients (35.6%) received chemotherapies because of the disease evolutions. The evolution rates were 16.6% at 1yr, 36.8% at 3 yr, and 62.5% at 5 yr (8.9% per year). The 3-yr OS after the start of treatments was 78.6%.Discussion: This is the largest scale retrospective study on the clinical courses of MGUS and sMM in Japan. The evolution rates to symptomatic MM from both MGUS and sMM were comparable with those of Western population previously reported from Mayo Clinic. On the other hand, since the survival rates of these patients after the evolution to symptomatic MM did not seem to be poor, it might be unnecessary in general to consider early chemotherapy before the evolution.