Impact of prior solid tumor on outcomes of allogeneic hematopoietic stem cell transplantation for AML or MDS.

Abstract

7048 Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) offers a definitive treatment of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Prior solid tumor (PST) is felt to portend a worse post-transplant prognosis. The aim of this study was to evaluate the impact of PST history on allo-HSCT outcome. Methods: We retrospectively identified patients with AML or MDS who underwent first allo-HSCT at the Fred Hutchinson Cancer Research Center between 2010 and 2018. Cox regression analysis was used to identify factors associated with mortality among patients with PST, and to compare outcomes of patients with and without PST. Multivariable models were fit, adjusting for cytogenetic risk level, time from PST diagnosis to transplant, receipt of reduced-intensity conditioning (RIC), and age at transplant. Survival estimates were obtained using the Kaplan-Meier method. Results: 1198 patients were included for analysis, of which 101 had a history of PST. After a median follow up of 1301 days among survivors, there was a total of 558 deaths and 322 relapses among all patients. Patients with history of PST were older (62.5 vs 54.9 yrs) and a higher proportion received RIC (52.5% vs 27.3%). The most common PSTs included breast (38/101, 38%), prostate (13/101, 13%), colon (9/101, 9%), thyroid (8/101, 8%), and uterine (7/101, 7%). Among those with known staging (n = 66), stage 1 (28/66, 42%) was the most common, followed by stage 2 (17/66, 26%) then stage 3 (15/66, 23%). The most common therapies provided were surgery (95/101, 95%), cytotoxic chemotherapy (41/101, 41%), radiation (45/101, 45%), and endocrine therapy (25/101, 25%). The unadjusted hazard ratio (HR) of mortality in the PST group relative to the non-PST group was 1.10 (95% confidence interval [CI] 0.83-1.47, p = 0.52). After adjustment for patient age, disease, patient/donor CMV status, KPS, cytogenetic risk, source of stem cells, and donor type, the adjusted HR was 0.91 (95% CI 0.68-1.22, p = 0.59). The unadjusted HR for relapse was 1.15 (95% CI 0.79-1.67, p = 0.48), and adjusted HR was 1.11 (0.76-1.11, p = 0.61). Among patients with PSTs, high-risk cytogenetics were associated with increased mortality (adjusted HR = 2.21; 95% CI 1.16-4.2, p = 0.016) and relapse (adjusted HR = 1.91; 95% CI 1.01-3.60, p = 0.047). Longer time from PST diagnosis to transplant led to a numerically increased mortality in the unadjusted (HR = 1.05; 95% CI 1.00-1.11, p = 0.057) and adjusted (HR = 1.05; 95% CI 1.00-1.11, p = 0.69) models treating time as a continuous linear variable. Conclusions: In our study, a history of PST did not impact overall survival or relapse rate among patients who underwent first allo-HSCT for AML or MDS. As in the overall population, post-transplant outcomes were primarily driven by cytogenetic risk level. However, it is likely that selection of patients with PST for transplantation was biased based on overall risk assessment.