Recent status in the occurrence of leukemia in growth hormone-treated patients in Japan

The Foundation for Growth Science in Japan has monitored the safety and eff icacy of GH treatment in GH-deficient patients since 1975. Data were collec ted from more than 32,000 patients up to December 31, 1997. New leukemia wa s observed in 14 patients and myelodysplastic syndrome (MDS) in one patient . The types of leukemia were acute lymphocytic leukemia (n = 6; 40%), acute myelocytic leukemia or MDS (n = 7; 47%), and chronic myelocytic leukemia ( n = 2; 13%). Leukemia developed in 9 patients during GH treatment and in 6 after the cessation of GH treatment. Six patients had known risk factors fo r leukemia, such as Fanconi's anemia and previous radiation or chemotherapy . Patient-years of GH therapy was defined as the time from the first dose o f GH to the date of the last visit during GH therapy, and patient-years of risk was defined as the time from the first dose of GH to December 31, 1997 . The incidence of leukemia of patient-years of GH therapy and patient-pear s of risk in GH-treated patients without risk factors was 3.0/100,000 and 3 .9/100,000, respectively, a figure similar to the incidence in the general population aged 0-15 yr. We conclude that the incidence of leukemia in GH-treated patients without r isk factors is not greater than that in the general population aged 0-15 yr , and a possible increased occurrence of leukemia with GH treatment appears to be limited to patients with risk factors.