Comparable Outcomes in Nonsecretory and Secretory Multiple Myeloma after Autologous Stem Cell Transplantation

Non-secretory myeloma (NSM) accounts for <5% of cases of multiple myeloma (MM). The outcome of these patients following autologous stem cell transplantation (ASCT) has not been evaluated in clinical trials. We compared the outcomes after ASCT for patients with NSM reported to the CIBMTR between 1989 and 2003, to a matched group of 438 patients (4 controls for each patient) with secretory myeloma (SM). The patients were matched using propensity scores calculated using age, Durie-Salmon stage, sensitivity to pre-transplant therapy, time from diagnosis to transplant and year of transplant. Disease characteristics were similar in both groups at diagnosis and at transplant except higher risk of anemia, hypoalbuminemia and marrow plasmacytosis (in SM) and plasmacytoma (more in NSM). Cumulative incidence of TRM, relapse, PFS and OS were similar between the groups. In multivariate analysis, based on a Cox model stratified on matched pairs and adjusted for covariates not considered in the propensity score, we found no difference in outcome between the NSM and SM groups. In this large cohort of patients undergoing ASCT, we found no difference in outcomes of patients with NSM compared to those with SM.