Long term mortality after a single treatment course with X-rays in patients treated for ankylosing spondylitis

Mortality up to 1 January 1983 has been studied in 14,106 patients with ankylosing spondylitis given a single course of X-ray treatment during 1935-54. For neoplasms other than leukaemia or colon cancer, mortality was 28% greater than that of members of the general population of England and Wales, and this increase is likely to have been a direct consequence of the treatment. The proportional increase reached a maximum of 71% between 10.0 and 12.4 years after irradiation and then declined. There were only a 7% increase in mortality from these tumours more than 25.0 years after irradiation and only for cancer of the oesophagus was the relative risk significantly raised in this period. Neither the magnitude of the relative risk, nor its temporal pattern following treatment, were greatly influenced by the age of the patient at first treatment. For leukaemia there was a threefold increase in mortality that is also likely to have been due to the radiotherapy. For colon cancer mortality was increased by 30%. For non-neoplastic conditions there was a 51% increase in mortality that was likely to be associated with the disease itself rather than its treatment. (author)