Utility of the Treatment-Related Mortality (TRM) score to predict outcomes of adults with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplantation

There is long-standing interest in estimating non-relapse mortality (NRM) after allogeneic hematopoietic cell transplantation (HCT) for AML, but existing tools have limited discriminative capacity. Using single-institution data from 861 adults with AML, we retrospectively examined the Treatment-Related Mortality (TRM) score, originally developed to predict early mortality following induction chemotherapy, as a predictor of post-HCT outcome. NRM risks increased stepwise across the four TRM score quartiles (at 3 years: 9% [95% confidence interval: 5–13%] in Q1 vs. 28% [22–34%] in Q4). The 3-year risk of relapse was lower in patients with lower TRM score (26% [20–32%] in Q1 vs. 37% [30–43%] in Q4). Consequently, relapse-free survival (RFS) and overall survival (OS) estimates progressively decreased (RFS at 3 years: 66% [59–72%] in Q1 vs. 36% [29–42%] in Q4; OS at 3 years: 72% [66–78%] in Q1 vs. 39% [33–46%] in Q4). With a C-statistic of 0.661 (continuous variable) or 0.642 (categorized by quartile), the TRM score predicted NRM better than the Pretransplantation Assessment of Mortality (PAM) score (0.603) or the HCT-CI/age composite score (0.576). While post-HCT outcome prediction remains challenging, these findings suggest that the TRM score may be useful for risk stratification for adults with AML undergoing allogeneic HCT.