Retrospective analysis of progression to multiple myeloma or related disorders in 114 patients with monoclonal gammopathy of undetermined significance in a single institute

: In 114 patients with monoclonal gammopathy of undetermined significance (MGUS) followed-up in Tachikawa Sougo hospital, we retrospectively analyzed progression of their disease to multiple myeloma (MM) or related disorders. The analysis was based on a total of 1,170 person-years of follow-up in a cohort with a median age at diagnosis of MGUS of 68 years 3 months, and with a median follow-up period of 9 years 5 months. Of these 114 patients, 13 (11%) showed progression to MM or related disorders with a median time to progression of 9 years 4 months; and the median age of these 13 patients was 78 years 8 months. The cumulative hazard ratio of progression at 5, 10, 15, and 20 years after diagnosis was 3.0%, 9.0%, 11.4%, and 32.1%, respectively. The risk of progression of MGUS to MM or related disorders in Japanese patients was as high as in Western patients studied previously, demonstrating that MGUS should be carefully monitored as a preneoplastic condition.