Patients undergoing autologous hematopoietic stem cell transplant (auto-HSCT) for lymphoma or myeloma have an increased risk of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), according to a retrospective study.
The study suggested these patients have 10 to 100 times the risk of AML or MDS as the general population.
The elevated risk also exceeds that of similar lymphoma and myeloma patients largely untreated with auto-HSCT.
Tomas Radivoyevitch, PhD, of the Cleveland Clinic Foundation in Ohio, and his colleagues reported these findings in Leukemia Research.
The investigators noted that exposure to DNA-damaging drugs and ionizing radiation—both used in auto-HSCT—is known to increase the risk of AML and MDS.
With this in mind, the team analyzed data on auto-HSCT recipients reported to the Center for International Blood and Marrow Transplant Research (CIBMTR).
Analyses were based on 9028 patients undergoing auto-HSCT from 1995 to 2010 for Hodgkin lymphoma (n=916), non-Hodgkin lymphoma (NHL, n=3546), or plasma cell myeloma (n=4566). Their median duration of follow-up was 90 months, 110 months, and 97 months, respectively.
Overall, 3.7% of the cohort developed AML or MDS after their transplant.
More aggressive transplant protocols increased the likelihood of this outcome. The risk of developing AML or MDS was higher for:
- Hodgkin lymphoma patients who received conditioning with total body radiation versus chemotherapy alone (hazard ratio [HR], 4.0)
- NHL patients who received conditioning with total body radiation (HR, 1.7) or with busulfan and melphalan or cyclophosphamide (HR, 1.8) versus the BEAM regimen (bischloroethylnitrosourea, etoposide, cytarabine, and melphalan)
- NHL or myeloma patients who received 3 or more lines of chemotherapy versus 1 line (HR, 1.9 for NHL and 1.8 for myeloma)
- NHL patients who underwent transplant in 2005 to 2010 versus 1995 to 1999 (HR, 2.1).
Patients reported to the Surveillance, Epidemiology and End Results database with the same lymphoma and myeloma diagnoses, few of whom underwent auto-HSCT, had risks of AML and MDS that were 5 to 10 times higher than the background level in the population.
However, the study auto-HSCT cohort had a risk of AML that was 10 to 50 times higher and a relative risk of MDS that was roughly 100 times higher than the background level.
“These increases may be related to exposure to high doses of DNA-damaging drugs given for [auto-HSCT], but this hypothesis can only be tested in a prospective study,” Dr Radivoyevitch and his coinvestigators wrote.
The reason for the greater elevation of MDS risk, compared with AML risk, is unknown.
“One possible explanation is that many cases of MDS evolve to AML, and that earlier diagnosis from increased post-transplant surveillance resulted in a deficiency of AML,” the investigators wrote. “A second is based on steeper MDS versus AML incidences versus age . . . and the possibility that transplantation recipient marrow ages (ie, marrow biological ages) are perhaps decades older than calendar ages.”
The study authors said they had no relevant conflicts of interest. The CIBMTR is supported by several US government agencies and numerous pharmaceutical companies.