The 1957 MRC report on leukaemia and aplastic anaemia in patients irradiated for ankylosing spondylitis.

The estimation of the carcinogenic effects of exposure to low doses of ionizing radiation has depended primarily on extrapolation from effects seen in two populations exposed to relatively high doses--the survivors of the atomic bomb explosions in Japan and patients treated in the UK with x-rays for the arthritic condition ankylosing spondylitis. The study of the leukaemia risk in over 14000 irradiated spondylitis patients was completed in an astonishingly short period of time in the mid-1950s. The full report of the original study has been difficult to access because it was not published in a journal but only as a Special Report of the UK Medical Research Council. To mark 50 years since this publication this full report is reproduced in this issue of the Journal. This accompanying review describes the background to the study, the principal findings and the further follow-up of the population that documented the risks of cancers in addition to leukaemia associated with the x-ray treatment. The architects of the study were a radiobiologist, Michael Court-Brown, and an epidemiologist, Richard Doll. Their very productive study of the leukaemia risk among spondylitics spawned a lifelong collaboration including further seminal studies of the carcinogenic effects of radiation exposure, which are also summarised in the review.