Therapy-related acute myeloid leukemia following treatment for cancer in childhood: A population-based registry study

Abstract

Background: Therapy-related acute myeloid leukemia (t-AML) is defined as AML that develops after exposure to cytotoxic chemotherapy and/or radiation therapy. There is a paucity of available literature, particularly in regard to t-AML following childhood cancer. Our aim was to describe the risk of t-AML among children treated for other cancers and their subsequent survival.

Procedure: We utilized data from the population-based Australian Childhood Cancer Registry to examine all childhood patients (<15 years at diagnosis) treated with chemotherapy and/or radiotherapy for cancers other than AML who received a subsequent diagnosis of AML between 1983 and 2014. Standardized incidence ratios (SIRs) were calculated to approximate the relative risk of being diagnosed with AML compared to the general population. Estimates of 5-year observed survival were obtained using the Kaplan-Meier method, with differences determined by the log-rank test.

Results: Fifty-eight of 11,753 patients in the study cohort (0.5%) were diagnosed with t-AML, an almost 50-fold higher risk than expected (SIR = 45.6, 95% confidence interval [CI] = 35.3-59.0). Five-year observed survival from the date of t-AML diagnosis was 31.2% (95% CI = 19.6-43.5%). A significant survival advantage was found for patients who underwent hematopoietic stem cell transplantation (HSCT) following diagnosis of t-AML, with a 5-year survival of 52.4% (29.7-70.9%) compared to 5.7% (0.4-22.6%) for those who did not have HSCT (P < 0.001).

Conclusions: Although rare, t-AML is an important potential late effect of childhood cancer therapy. Prognosis is generally poor, with HSCT offering some survival benefit.

Keywords: Australia; population-based; relative risk; survival; therapy-related acute myeloid leukemia.