Second malignancies after autologous hematopoietic cell transplantation in children

Childhood autologous hematopoietic cell transplant (auto-HCT) survivors can be at risk for secondary malignant neoplasms (SMNs). We assembled a cohort of 1487 pediatric auto-HCT recipients to investigate the incidence and risk factors for SMNs. Primary diagnoses included neuroblastoma (39%), lymphoma (26%), sarcoma (18%), central nervous system tumors (14%) and Wilms tumor (2%). Median follow-up was 8 years (range, <1-21 years). SMNs were reported in 35 patients (AML/myelodysplastic syndrome (MDS) = 13, solid cancers = 20, subtype missing = 2). The overall cumulative incidence of SMNs at 10 years from auto-HCT was 2.60% (AML/MDS = 1.06%, solid tumors = 1.30%). We found no association between SMNs risk and age, gender, diagnosis, disease status, time since diagnosis or use of TBI or etoposide as part of conditioning. OS at 5-years from diagnosis of SMNs was 33% (95% confidence interval (CI), 16-52%). When compared with age- and gender-matched general population, auto-HCT recipients had 24 times higher risks of developing SMNs (95% CI, 16.0-33.0). Notable SMN sites included bone (N=5 SMNs, observed (O)/expected (E) = 81), thyroid (N = 5, O/E = 53), breast (n = 2, O/E = 93), soft tissue (N = 2, O/E = 34), AML (N = 6, O/E= 266) and MDS (N = 7, O/E = 6603). Risks of SMNs increased with longer follow-up from auto-HCT. Pediatric auto-HCT recipients are at considerably increased risk for SMNs and need life-long surveillance for SMNs. Bone Marrow Transplantation (2013) 48, 363-368; doi:10.1038/bmt.2012.166; published online 10 September 2012