LONG TERM EFFECTS OF X-RAY THERAPY FOR METROPATHIA HAEMORRHAGICA

Between the years 1940 and 1960, radiotherapists in Aberdeen, Dundee, and Edinburgh used x-irradiation of the ovaries to advance the age of menopause in women suffering from excessive uterine bleeding. The treatment delivered a dose of about 6 Gy on average to the ovaries and the women's subsequent health can, therefore, provide an indication of the carcinogenic effect of such doses of low linear energy transfer radiation on the pelvic organs.

Two thousand and sixty seven women who were treated in this way have been identified in hospital records, 97 per cent of whom were treated for metropathia haemorrhagica and 3 per cent for other benign gynaecological conditions, and reports of their mortality experience up to the end of 1963 and up to about the end of 1972 have been published.1, 2 The results showed that the women experienced an increased risk of leukaemia and of cancers of heavily irradiated sites in the pelvis, and suggested that the relative risk of developing these cancers diminished with time some years after exposure. They also showed that the risk of breast cancer was decreased and the risk of ischaemic heart disease unaffected. Most of the results accorded well with other observations on irradiated subjects, but there is a need to review the extent of the leukaemia excess in the light of the revised estimates of risk based on the survivors of the Hiroshima and Nagasaki explosions that are now available,3 and the finding of a relatively small excess leukaemia risk among patients treated with radiotherapy for cervical cancer.4 In addition the suggestion of a decrease in the relative risk of developing cancer in solid organs more than 15 years after exposure is contrary to what has been observed in the Hiroshima and Nagasaki survivors,5 and the difference in the effect of destruction of ovarian function on the subsequent mortality rates from breast cancer and coronary artery disease was surprisingly great.