Follow-up study of late effects in 224Ra treated ankylosing spondylitis patients.

We are following 1531 patients treated with 224Ra from 14 hospitals in the F.R.G. and 267 control patients with ankylosing spondylitis not treated with any form of ionizing radiation. Since 1970 three cases of malignant tumour in the skeleton have been found among 224Ra-treated patients with skeletal doses below 90 rad compared with 0.4-0.6 expected. Two of these three cases were tumours of the bone marrow. An effect of 224Ra on the haematopoietic system cannot be excluded. Also, seven cases of cataract were found among 274 224Ra patients. The mean time since 224Ra treatment was 26 yr. The mean age at diagnosis was 66 yr. The cataract incidence was not unusual for people of this age.