RISK OF LEUKEMIA IN CHILDREN TREATED WITH HUMAN GROWTH-HORMONE - REVIEW AND REANALYSIS

Background: Data have suggested that any increased incidence of leukem ia in growth-hormone (GH)-treated patients mas limited to those with k nown risk factors for leukemia. However, previous studies may have ove restimated the numbers of patient-years of risk by not excluding data from ''positive-risk-factor'' patients. This risk was reanalyzed by us ing data on children in the National Cooperative Growth Study (NCGS), with correction for this possible confounding factor. Methods: The ris k of leukemia in GH-treated patients without known risk factors was de termined by using patient-years of GH therapy and patient years since first exposure to GH therapy and the values obtained were compared wit h values fr om the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. Results: Three cases of leukemia in patients without known risk factors were found in the NCGS database; 3.42 cases would be expected in the 119,846 patient-years in the analy sis using time since GH exposure. Two of these cases of leukemia occur red during CH therapy (67,773 patient-years); 2.13 cases would be expe cted. Conclusion: Excluding data on patients with known risk factors f or leukemia provides a more accurate estimate of the risks in GH-treat ed patients. The incidence of leukemia in these patients is comparable to that in the general population of age-matched children.