Multiple Basal Cell Carcinomas in two cases of ankylosing spondylitis treated with X-ray therapy

Skin cancers were the first malignancies described in association with ionising radiation (Freiben, 1902). In spite of this, the induction rates for these tumours remains uncertain (UNSCEAR 1977, pp. 293–302). Some observations suggest a low rate of induction (Shore et al, 1976) and this view is expressed in certain authoritative texts (e.g., Cancer Medicine, 1982). Evidence for a higher rate of induction can be found however (Pegum, 1972; Sarkany et al, 1968) and we present two cases in which multiple skin tumours were almost certainly induced by X radiation given for ankylosing spondylitis. Reasons for the apparent discrepancies in induction rates for radiation-induced skin cancer are then discussed. In 1983 a 63-year-old man was referred to the Hammersmith Hospital by his dermatologist. He had developed symptoms of ankylosing spondylitis in 1940 and in 1943 received radiotherapy, details of which are given in Table I. There followed a marked improvement in his mobility and his painful symptoms resolved. He returned to his occupation as a sheet metal worker and suffered no further serious problems from his ankylosing spondylitis. For the last 10 years he has taken biannual holidays in hot climates and is a keen sunbather. In 1982, 39 years after his X-ray treatment, he developed several abnormal areas on the skin of his back. These were asymptomatic.