Sex-based Differences in Risk for Therapy-related Myeloid Neoplasms

PURPOSE Therapy-related myeloid neoplasm (t-MN) is a life-threatening complication of autologous peripheral blood stem cell (PBSC) transplantation for non-Hodgkin lymphoma (NHL). Previous studies report an association between clonal hematopoiesis (CH) in PBSC and risk of t-MN, but small samples precluded examination of risk within specific subpopulations. METHODS Targeted DNA sequencing was performed to identify CH mutations in PBSC from a retrospective cohort of 984 patients with NHL (median age at transplant, 57 years; range, 18-78). Fine-Gray proportional subdistribution hazard regression models estimated association between number of CH mutations and t-MN, adjusting for demographic, clinical, and therapeutic variables. Secondary analyses evaluated the association between CH and t-MN among males and females. RESULTS CH was identified in PBSC from 366 patients (37.2%). t-MN developed in 60 patients after a median follow-up of 5 years. Presence of ≥2 mutations conferred increased t-MN risk (adjusted hazard ratio [aHR], 2.10; 95% CI [1.08 to 4.11]; P = .029). CH was associated with increased t-MN risk among males (aHR, 1.83 [95% CI, 1.01 to 3.31]) but not females (aHR, 0.56 [95% CI, 0.15 to 2.09]). Although the prevalence and type of CH mutations in PBSC were comparable, the 8-year cumulative incidence of t-MN was higher among males vs. females with CH (12.4% v 3.6%) but was similar between males and females without CH (4.9% v 3.9%). Expansion of CH clones from PBSC to t-MN was seen only among males. CONCLUSION presence of CH mutations in PBSC confers increased risk of t-MN after autologous transplantation in male but not female patients with NHL. Factors underlying sex-based differences in risk of CH progression to t-MN merit further investigation.