Incidence and outcomes of subsequent malignancy after allogeneic hematopoietic stem cell transplantation in adult patients with severe aplastic anemia.

PURPOSE

This study investigated the occurrence of subsequent malignancies (SM) in adult patients with severe aplastic anemia (SAA) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) to address the lack of large-scale, long-term data on this complication.

METHODS

A retrospective cohort analysis of 376 adult patients with SAA who underwent allo-HSCT between 2002 and 2021 at a single center was conducted. The incidence, risk factors, and survival impact of SM were also examined.

RESULTS

During the follow-up period, 31 cases of SM (8.2%) were identified. Approximately one-third (32.3%) of SM cases were hematologic malignancies, including post-transplant lymphoproliferative disorder (16.1%), myelodysplastic neoplasm (6.5%), and acute myeloid leukemia (3.2%). Solid tumors accounted for 67.7% of cases, with thyroid cancer being the most prevalent (25.8%). The 15-year cumulative incidence of SM was 11.2%, and the hazard ratio for overall survival according to the development of SM was 16.25 (p < 0.001). High-dose total body irradiation (TBI), anti-thymocyte globulin (ATG), and moderate-to-severe chronic graft-versus-host disease (GVHD) were identified as significant risk factors for subsequent malignancy. Post-transplant SAA patients exhibited a 3.54-fold higher observed cancer incidence than the expected incidence calculated from the age-, sex-, and calendar year-matched general population.

CONCLUSION

SM is a significant long-term complication in patients with posttransplant SAA and has a substantial survival impact. Patients receiving high-dose TBI or ATG, and those with moderate-to-severe chronic GVHD, require vigilant long-term monitoring.