To the Editor.
—In the June Archives, Finnerty et al1 reported that 1.7% of 912 patients with breast cancer without distant metastases gave a history of irradiation to the chest between ages 1 and 22 years. They stated that, in most instances, the exact dose and dose fraction were not known. Nevertheless, they made the remarkable assumption that the radiation caused the breast cancers after a median latency period of 420 months.It may be that radiation is a possible cause of breast cancer. There are other possible causes. It would be interesting to obtain a careful history from 1,000 women with a median age of 52 years (range, 26 to 76 years), who have no evidence of breast cancer. If a history of exposure to ionizing radiation similar to that described was not obtained from at least 2%, it would be truly remarkable.Irrational fear of ionizing radiation