Despite recommendations and an increased risk of breast cancer, most young women who were treated with chest radiation for a childhood cancer do not undergo appropriate mammography screening, according to a study published in today’s issue of the Journal of the American Medical Association.
”The risk of breast cancer begins to increase as early as eight years after radiation and the median [midpoint] age of breast cancer diagnosis ranges from 32 to 35 years," the authors wrote. By age 45 years, it is estimated that from 12 to 20 percent of women treated with moderate- to high-dose chest radiation will be diagnosed with breast cancer.
To characterize the breast cancer surveillance practices among female pediatric cancer survivors who were treated with chest radiation and identify correlates of screening, Kevin C. Oeffinger, MD, of Memorial Sloan-Kettering Cancer Center in New York City, and colleagues administered a 114-item questionnaire to a random sample of 625 women aged 25 through 50 years who had survived pediatric cancer, who had been treated with chest radiation and who were participating in the Childhood Cancer Survivor Study (CCSS), between June 2005 and August 2006.
Comparisons were made with similarly aged pediatric cancer survivors not treated with chest radiation and the CCSS sibling cohort—a North American cohort of long-term cancer survivors diagnosed from 1970-1986.
Of 1,976 cancer survivors and siblings who were contacted, 87.9 percent participated.
Among the 551 women with a history of chest radiation, 55 percent reported a screening mammogram in the past two years. In comparison, 40.5 percent of survivors without chest radiation and 37 percent of CCSS siblings reported a screening mammogram in the same time interval.
Notably, among women with a history of chest radiation, 47.3 percent of women younger than 40 years had never had a mammogram and only 52.6 percent of women aged 40 through 50 years were being regularly screened (two mammograms within four years).
According to the authors, screening rates were higher among women who reported a physician recommendation than those who did not, and in multivariate models, the association was particularly strong for younger women.
“In this cohort of women who had childhood cancer treated with chest radiation, 63.5 percent of those aged 25 through 39 years and 23.5 percent of those aged 40 through 50 years had not had mammography screening for breast cancer within the previous two years despite a guideline recommendation that survivors of childhood cancer who were treated with chest radiation should undergo annual screening mammography,” the authors wrote.
"These include the relatively low uptake of screening mammography in a high-risk population, the importance of clinician recommendation to improve the uptake of screening mammography, and the continuing need to educate clinicians and patients about the risks of breast cancer after chest irradiation in childhood through well-designed education programs,” wrote Aliki J. Taylor, MD, PhD, of the University of Birmingham in England, and Roger E. Taylor, MD, of Swansea University in Wales, in an accompanying editorial.
“The risk of breast cancer after exposure to annual low-dose irradiation in the form of x-ray mammography should be explored in future studies as well as the role of [MRI] as a replacement for x-ray mammography rather than as an adjunctive examination in this group of young women. In addition, it is important to explore whether the rate of screening uptake could be improved if survivors were provided with screening at no extra cost,” Taylor and Taylor concluded.