Breast X-Ray

It is well known that high doses of ionizing radiation increase risk for breast cancer. Examples are exposure to the atomic bomb explosions in Japan (particularly if exposure occurred before age 30), and therapeutic radiation to the chest area, such as for Hodgkin's lymphoma. E M John and others report an increased risk of 3.55 fold following previous therapeutic radiation. Risk conferred by diagnostic x rays to the spine is harder to quantify. A study from the Breast Cancer Family Registry Int J Cancer. 2007 Jul 15;121(2):386-94 found that diagnostic chest x rays for TB or pneumonia increased breast cancer risk 2 fold. Chest x rays for other conditions, spine x rays, and cardiac catheterization did not increase breast cancer risk.
There are several reports regarding risk associated with x rays for scoliosis specifically. D A Hoffman and others studied 1,030 women with scoliosis who were seen at four Minneapolis area medical facilities between 1935 and 1965 J Natl Cancer Inst 81:1307–1312, 1989. 11 cases of breast cancer were reported, compared with six expected. Their conclusion was that frequent exposure to low-level diagnostic radiation during childhood or adolescence may increase the risk of breast cancer.
C M Ronckers and others performed a retrospective analysis of 3,010 women, diagnosed with spinal curvature between 1912 and 1965 in 14 U.S. pediatric orthopedic centers Cancer Epidemiol Biomarkers Prev 2008;17(3):605–13. They reported 78 cases of breast cancer after 118,905 woman-years of follow-up, median follow-up 35.5 years. They concluded that women with abnormal spinal curvature who were exposed to diagnostic x rays during childhood and adolescence were at increased risk of breast cancer, with a borderline statistically significant radiation dose-response relationship. Patients who reported having female blood relatives with breast cancer appeared to be at higher risk of radiation-related breast cancer than those who did not report such family history. Regarding what to do about these findings the authors state, "for women exposed to multiple x rays in the past, compliance with current breast cancer screening guidelines is warranted. Health-care practitioners should be aware that women with a history of scoliosis may be at increased risk of breast cancer".