Second Cancer Risk and Late Mortality in Adult Australians Receiving Allogeneic Hematopoietic Stem Cell Transplantation: A Population-Based Cohort Study

We quantified the risk of second cancer and late mortality in a population-based Australian cohort of 3273 adult (≥15 years) allogeneic hematopoietic stem cell transplant recipients (1992 to 2007). Most recipients received nonradiation-based conditioning and a peripheral blood graft from a matched related donor. Using record linkage with death and cancer registries, 79 second cancers were identified a median of 3.5 years after transplantation. The competing-risk adjusted cumulative incidence of second cancers was 3.35% (95% CI, 2.59 to 4.24) at 10 years, and the cancer risk relative to the matched general population was 2.10 (95% CI, 1.65 to 2.56). We observed an excess risk of melanoma and lip, tongue, esophagus, and soft tissue cancers. Cancer risk relative to the general population was elevated for those transplanted for lymphoma, some leukemia subtypes, and severe aplastic anemia, recipients who developed chronic graft-versus-host disease (cGVHD) and irrespective of radiation-based conditioning or stem cell source. In those alive 2 years after transplantation (n = 1463), the cumulative incidence of late mortality was 22.2% (95% CI, 19.7 to 24.9) at 10 years, and the risk of death relative to the matched general population was 13.8 (95% CI, 12.2 to 15.6). In multivariable modeling, risk of late death was reduced for females compared with males and those transplanted for chronic myeloid leukemia compared with acute myeloid leukemia; risk was increased for recipients with discordant sex donors, cGVHD, those undergoing second transplants, and disease relapse. Adults undergoing allogeneic transplantation have unique cancer and mortality risk profiles that continue to warrant prevention and surveillance activities targeted at high-risk subgroups.