Outcomes of therapy-related acute lymphoblastic leukemia in adults after allogeneic stem cell transplantation

Therapy-related acute lymphoblastic leukemia (t-ALL) is an increasingly recognized subset of therapy-related acute leukemia. There are limited data on the role of allogeneic hematopoietic stem cell transplantation (HSCT) in t-ALL. Recent reports suggest comparable outcomes of t-ALL with de novo ALL after HSCT.

We retrospectively reviewed all patients of t-ALL who underwent HSCT at our center. Patients were analyzed for prior malignancy, therapy, time to diagnosis of t-ALL, clinical, laboratory characteristics, transplant details, relapse-free survival (RFS), and overall survival (OS).

Eighteen patients (M:F ratio 1:1; Median age 44 years) underwent HSCT for t-ALL. Median latent period from primary malignancy to t-ALL was 44.8 months. 11q23 rearrangement and t(9;22) were present in 33.3% and 22.2% patients, respectively. Stem cell donors were matched related, matched unrelated, and haploidentical in 27.8% (n = 5), 55.6% (n = 10), and 16.7% (n = 3) patients, respectively. Five patients died before D+ 100 (27.8%). Estimated 2-year RFS and OS were 47.1% and 51.8%, respectively. We did not find any pretransplant and post-transplant risk factors that were predictive of improved OS or RFS after multivariate analysis.

Allogeneic HSCT outcomes in t-ALL were comparable to HSCT outcomes in de novo ALL. Multicenter studies with more patients and longer follow-up may provide factors affecting outcome and survival.