Late Recurrence a Concern for AML After ASCT

Patients with acute myeloid leukemia (AML) who have undergone autologous stem cell transplantation (ASCT) and survived without disease recurrence for at least 2 years are still at risk for late recurrences, according to the results of a large retrospective study published in Cancer.

Prior research had shown that disease recurrence in these patients occurred mainly within the first 2 years after transplant, indicating that patients without recurrence in that time period had a good prognosis.

“Results from the current study clearly indicate that this assumption is incorrect, because the cumulative recurrence incidence at 10 years reached 16%, which represented the major cause of treatment failure among long-term survivors,” wrote researcher Tomasz Czerw, MD, of Maria Sklodowska-Curie Memorial Cancer Centre and Institute of Oncology, Poland, and colleagues.

The researchers conducted this study to identify which characteristics could help to identify patients who survived free from disease recurrence 2 years or longer after undergoing transplant.

The study included 3,567 adults with AML who underwent transplant during first or second complete remission from 1990 to 2008.  The transplant source was bone marrow for 32% of patients and peripheral blood for 68% of patients.

Among this group of patients, the probability of leukemia-free survival at 5 years was 86% and at 10 years it was 76%. At 5 years, the recurrence incidence was 11%, but by 10 years it had increased to 16%.

A multivariate analysis of the data identified increasing patient age, peripheral blood grafts, and adverse French–American–British (FAB) subtypes, including subtypes M0, M6, or M7, as all associated with an increased risk for disease recurrence.

“Unfortunately, data regarding cytogenetics were missing for a significant percentage of patients, which was partially due to the fact that approximately 50% of the patients in the current study were diagnosed before the year 2000, when the availability of such tests was low,” the researchers wrote. “Nevertheless, the prognostic significance of cytogenetics was apparent in a univariate analysis, and karyotype risk groups were strongly associated with FAB subtypes.”

According to the researchers, the observed survival seen in these patients was shorter than that of the expected survival of the age-matched and sex-matched general European population. According to the researchers, this observation indicates a need for longer follow-up of patients’ remission status as a standard clinical practice.

“The potentially encouraging finding of the current study might be that, in such long-term survivors, toxicity from the ASCT preparative conditioning might have sufficiently resolved to make subsequent allogeneic transplant more likely to be feasible at a later time point in disease management,” the researchers wrote.