Mortality from leukemia after irradiation in infancy for skin hemangioma.

From 1920 through 1959, 14,624 infants were exposed to ionizing radiation for skin hemangioma at Radiumhemmet. They were all less than 18 months old (mean 6 months) at the time of first exposure. The irradiated hemangiomas were located all over the body. The weighted bone marrow dose was on average 0.13 Gy (range < 0.01-4.6 Gy). During the period 1920-1986, 20 deaths from leukemia (11 childhood and 9 adult) were observed in the cohort compared with 17 expected during the same period. There were no significant associations between childhood leukemia and radiation dose. Despite the relatively large number of infants studied, the low average dose to bone marrow limited the possibility of detecting a small radiation risk as might be predicted from other radiation studies.