Exploring the aftermath of hematopoietic cell transplantation: 18-year insights into post-transplant neoplasms

Abstract Introduction: Survival post-hematopoietic stem cell transplantation (HCT) is improving, with an increasing number of survivors. Subsequent neoplasms (SNs) following HCTs are of particular concern. Methods: Between January 2003 and December 2022, HCT recipients' records were retrospectively reviewed. Results: At a median follow-up of 108 months (range, 0.13-215), 2659 patients received HCTs. Of those, 1131 (43%) were <18 years old. Allogeneic HCTs were conducted in 1476 (56%) patients. Myeloablative conditioning (MAC) was utilized in 2157 (81%), and 583(22%) received TBI. At a median of 9 years following transplant, forty-three patients developed SNs (1.6%) with a median age at time of HCT of 27.6 years (range, 2.8-64.8). Of those: 32 were males (74%), 20 received full HLA-matched allogeneic HCTs (46.5%), two (4.6%) had unrelated cord blood HCT (UCB), and one (2.3%) received haplo-HCT, whereas autologous HCTs accounted for 46.6% (n=20). Underlying diseases were: ALL(13.9%), AML(11.6%), Hodgkin Lymphoma(13.9%), Non-Hodgkin lymphoma(13.9%), Multiple Myeloma(18.6%), Fanconi Anemia(6.9%), CML(6.9%),Neuroblastoma(2.3%), and thalassemia (2.3%).); cGVHD occurred in (74%), and CMV infection/reactivation in (60.5%). Stem cell source included peripheral blood in (81.4%), BM in (3.9%), and UCB in (4.7%). Conditioning regimens were MAC (81.4%) vs RIC (18.6%). TBI-based regimen was utilized in 14 patients (32.5%). Subsequent hematologic malignancies accounted for 32.5% of SNs. While subsequent solid neoplasms occurred in 65.2%, and PTLD occurred in 2.3%. The probability of 5-year overall survival after a SN was 58.2%. Conclusions: SNs adversely impact the overall survival and quality of life of HCT survivors. In our cohort, the rate of post-HCT SNs was lower than that in the literature; however, longer follow-up of our cohort is needed.