Despite recommendations and being at 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 in the January 28 issue of JAMA1.
Women treated with chest radiation for a pediatric malignancy face a significantly increased risk of breast cancer at a young age. “The risk of breast cancer begins to increase as early as 8 years after radiation and the median [midpoint] age of breast cancer diagnosis ranges from 32 to 35 years,” the authors write. By age 45 years, it is estimated that from 12 percent to 20 percent of women treated with moderate- to high-dose chest radiation will be diagnosed with breast cancer.
Experts recommend annual screening mammography for women exposed to moderate- to high-dose chest radiation, starting at 25 years of age or 8 years after radiation, whichever occurs last. It is estimated that in the
Kevin C. Oeffinger, M.D., of Memorial Sloan-Kettering Cancer Center, New York, and colleagues conducted a study that included 625 women, age 25 through 50 years, who had survived pediatric cancer, had been treated with chest radiation and were participating in the Childhood Cancer Survivor Study (CCSS), a North American group of long-term survivors diagnosed from 1970-1986. Participants received a 114-item questionnaire. Comparisons were made with similarly aged pediatric cancer survivors not treated with chest radiation (n = 639) and the siblings of the CCSS group (n = 712). Of 1,976 cancer survivors and siblings who were contacted, 87.9 percent participated.
Among women age 25 through 39 years who had received chest radiation therapy (RT), 36.5 percent reported a screening mammogram within the past 2 years; 47.3 percent had never had a mammogram; and only 23.3 percent had a screening or diagnostic mammogram within the previous year.
Women age 40 through 50 years who had received chest RT were more likely to report mammography than their younger counterparts, with 76.5 percent reporting a screening mammogram within the past 2 years compared with 70.0 percent for the group without chest RT and 67.0 percent for the CCSS sibling group. Only 52.6 percent of women in this age group with chest RT had regular screening (at least 2 mammograms within 4 years). This was not significantly higher than for women with no chest RT and only modestly higher than the CCSS siblings.
In all groups, women who were older were more likely to have been screened in the prior 2 years or to have received regular screening. For each 5-year incremental increase in age, the likelihood of reporting a mammogram increased nearly 2-fold. The strongest predictor of mammography in women ages 25 through 39 years was having a physician recommend the test, with the likelihood of reporting a mammogram 3 times higher among women who reported a physician recommendation than women who did not.
“In summary, our study suggests that most young women at risk of breast cancer following chest radiation for a pediatric cancer, including women at highest risk (Hodgkin lymphoma survivors), are not being appropriately screened. Findings from this study should provide the foundation for targeted interventions involving both clinicians and cancer survivors,” the authors conclude.
In an accompanying editorial2, Aliki J. Taylor, M.D., M.P.H., Ph.D., of the University of Birmingham, United Kingdom, and Roger E. Taylor, M.D., M.A., of
“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. 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 magnetic resonance imaging 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.”
1. JAMA. 2009;301:404-414.
2. JAMA. 2009;301:435-436.