Allogeneic hematopoietic stem cell transplantation in patients with therapy-related hematologic malignancies...

Increasing survival of patients with multiple myeloma (MM) has resulted in an increased recognition of therapy-related hematological malignancies (t-MDS/AML, t-ALL, and t-CMML). There are limited data on the role of allogeneic hematopoietic stem cell transplantation (HCT) in this patient population.

We retrospectively reviewed patients who underwent HCT for t-MDS/AML, t-ALL, and t-CMML developing after receiving treatment for MM at our center. Patients were analyzed for myeloma characteristics and therapy, time to diagnosis of therapy-related hematological neoplasms, clinical, laboratory characteristics, transplant details, relapse-free survival (RFS), and overall survival (OS).

Twenty patients underwent HCT for therapy-related hematological malignancies after MM (t-MDS/AML = 13, t-ALL = 6, t-CMML = 1). Median(range) age at time of transplant was 62.5 (49-73) years and 70% (n = 14) were male. The most common cytogenetic abnormality was complex/monosomal karyotype in 30% (n = 6) followed by monosomy/deletion of chromosome 5 or 7 in 15% (n = 3) of patients each. Donors were human leukocyte antigen matched (10/10 or 6/6) siblings in 30% (n = 6), unrelated in 60% (n = 12) and haploidentical in 10% (n = 2) patients. Estimated 2-year OS and RFS for the whole cohort were 53.1% and 47.2% respectively. There was a trend toward better survival in patients with t-ALL when compared to t-MDS/AML; however, the difference was not statistically significant. We did not find any pre-transplant or post-transplant factors that were predictive of survival outcomes after multivariate analysis.

Allogeneic HCT provides substantial long-term disease-free survival in a proportion of patients with MM-associated therapy-related hematological malignancies. Multicenter studies with more patients and longer follow-up may provide additional information about factors affecting outcomes.