Patients undergoing autologous hematopoietic cell transplantation for lymphoma or plasma cell myeloma have 10-100 times the risk of acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) seen in the general population, according to a retrospective cohort study.
The elevated risk also exceeds that of similar patients largely untreated with autotransplant.
Exposure to DNA-damaging drugs and ionizing radiation – both used in autotransplant – is known to increase risk of these treatment-related myeloid neoplasms, according to Tomas Radivoyevitch, PhD, of the Cleveland Clinic Foundation and his colleagues. Concern about this complication has been growing as long-term survivorship after transplant improves.
The investigators analyzed data reported to the Center for International Blood and Marrow Transplant Research. Analyses were based on 9,028 patients undergoing autotransplant during 1995-2010 for Hodgkin lymphoma (916 patients), non-Hodgkin lymphoma (3,546 patients), or plasma cell myeloma (4,566 patients). 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 transplantation protocols increased the likelihood of this outcome: Risk was higher for patients with Hodgkin lymphoma who received conditioning with total body radiation versus chemotherapy alone (hazard ratio, 4.0); patients with non-Hodgkin lymphoma who received conditioning with total body radiation (HR, 1.7) or with busulfan and melphalan or cyclophosphamide (HR, 1.8) versus the BEAM regimen; patients with non-Hodgkin lymphoma or plasma cell myeloma who received three or more lines of chemotherapy versus just one line (HR, 1.9 and 1.8, respectively); and patients with non-Hodgkin lymphoma who underwent transplantation in 2005-2010 versus 1995-1999 (HR, 2.1).
Patients reported to Surveillance, Epidemiology and End Results (SEER) database with the same lymphoma and plasma cell myeloma diagnoses, few of whom underwent autotransplant, had risks of AML and MDS that were 5-10 times higher than the background level in the population. But the study autotransplant cohort had a risk of AML that was 10-50 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 the autotransplant, 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 posttransplant surveillance resulted in a deficiency of AML,” they wrote. “A second is based on steeper MDS versus AML incidences versus age … and the possibility that transplantation recipient marrow ages (i.e., marrow biological ages) are perhaps decades older than calendar ages.”
The Center for International Blood and Marrow Transplant Research is supported by several U.S. government agencies and numerous pharmaceutical companies. The authors reported that they had no relevant conflicts of interest.
SOURCE: Radivoyevitch T et al. Leuk Res. 2018 Jul 19. .