Retrospective Survival Analysis of Multiple Myeloma Patients after Autologous Hematopoietic Stem Cell Transplantation

Abstract

Background. Autologous hematopoietic stem cell transplantation (auto-HSCT) is an indispensable treatment stage in patients with newly diagnosed multiple myeloma (MM) who are, based on age and health status, eligible for high-dose chemotherapy with subsequent auto-HSCT. However, the issue of double (tandem) auto-HSCT feasibility remains unresolved. Aim. To compare overall survival (OS) and progression-free survival (PFS) in MM patients after single and double (tandem) auto-HSCTs in clinical practice. Materials & Methods. Retrospective analysis enrolled 83 MM patients divided into two groups: with single (n = 41) and double (n = 42) auto-HSCTs. Median age in groups 1 and 2 was 58 years (range 42-68) and 54 years (range 40-65), respectively. In these groups there were 16 (39 %) and 11 (26.2 %) patients > 60 years old. The reference point of survival curve was the date of first (in group 1) and 2nd (in group 2) auto-HSCTs. In PFS assessment, completed event was the date of disease progression or relapse detection, including the biochemical one in case of specific therapy onset. Results. Total number of patients with > very good partial response before receiving auto-HSCT in group 1 was 23 (56.1 %), and in group 2 before receiving 2nd auto-HSCT it was 30 (71.4 %). Mel200 conditioning was administered to 53.7 % of patients in group 1. In group 2 this conditioning regimen was a priority in performing first auto-HSCT (83.3 % of patients) and was more rarely used in case of repeated transplantation (40.5 %). With median follow-up of 11 and 40.5 months in groups 1 and 2 no significant differences were identified either in median PFS (21 and 40 months; p = 0.154) or in median OS (not reached in both groups; p = 0.882). No differences between groups with respect to the time before relapse/progression or early relapse rate were observed. Conclusion. Repeated auto-HSCT showed no additional antitumor effect. It can be accounted for by the lack of data on chromosome aberrations at the disease onset in most patients and by a small number of patients in the groups. Nevertheless, it was decided to limit the number of tandem auto-HSCTs and to perform 2nd transplantation mostly in case of late relapse/progression. New studies were initiated which will focus on the search of predictors associated with survival improvement in MM patients while performing double (tandem) auto-HSCTs.