Malignancies in patients treated with high doses of radium-224

Predominantly from 1945 to 1955, a group of patients in Germany was treated with multiple injections of the short-lived alpha-particle emitter Ra-224. Th, patients suffered from ankylosing spondylitis, tuberculosis and in a f ew cases from other diseases. The "Spiess study" (study I) follows up the h ealth of 899 of these patients; it includes most of the patients who were t reated with high doses (mean bone surface dose: 30 Gy, mean specific activi ty: 0.66 MBq/kg), and nearly all of those treated under the age of 21 years , The most striking consequence of the Ra-224 injections was the occurrence of 56 malignant bone tumors. They appeared in a temporal wave that peaked around 8 years after exposure. A new analysis was recently performed, becau se a reassessment of the dosimetry resulted in changed bone surface doses, especially for the patients treated at younger ages. Averaged over all ages at exposure, the estimated risk coefficient is in general agreement with e arlier analyses, However, there is now an increase in bone tumor risk that is significantly greater for younger ages at exposure. The earlier finding of an inverse protraction factor is confirmed. During the most recent years of follow-up, a significant excess of nonskeletal solid malignancies has b ecome manifest. In 1998, a significant increase of breast cancer incidence, of soft tissue malignancies, of thyroid carcinomas, and of liver, kidney a nd bladder cancer was found. An eightfold increased risk of mammary cancers in those treated at a young age is particularly striking. Equally notable are two cases of breast cancer in male patients. To identify potential conf ounders, a control group of tuberculosis patients not treated with Ra-224 w as established, The comparison confirms that the Ra-224 treatment is respon sible for most of the excess of mammary cancer. (C) 1999 by Radiation Resea rch Society.