Jan. 27, 2009 -- Women who underwent chest radiation therapy for a childhood cancer have a significantly higher risk for developing breast cancer at a younger age. Yet a new study in the Journal of the American Medical Association shows that many of them do not undergo the recommended screenings.
"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," Kevin C. Oeffinger, MD, of Memorial Sloan-Kettering Cancer Center in New York, and colleagues write.
About 20,000 to 25,000 women 25 and older in the U.S. have received chest radiation for a childhood cancer, according to background information in the journal report. For the past decade, experts have recommended yearly screening mammograms for women who received moderate- to high-dose chest radiation beginning either at age 25 or eight years after the treatment, whichever occurs last.
But some women in the new study had never even had a mammogram.
About 12% to 20% of women who receive moderate- to high-dose chest radiation for a childhood cancer will be diagnosed with breast cancer by age 45, but some develop the disease much earlier. "The risk of breast cancer begins to increase as early as 8 years after radiation and the [midpoint] age of breast cancer diagnosis ranges from 32 to 35 years," Oeffinger's team writes.
Oeffinger and colleagues based their findings on a 114-item questionnaire filled out by 625 female participants, aged 25 to 50, of the Childhood Cancer Survivors Study (CCSS). All the women had survived childhood cancer and had been treated with chest radiation.
The researchers compared the women's responses to similarly aged childhood cancer survivors who did not receive chest radiation, and siblings with no history of childhood cancer.
Among women 25 to 39 who had received chest radiation for childhood cancer:
- Most (47.3%) never had a mammogram.
- 63.5% had not received a screening mammogram within the past two years, despite guidelines that recommend annual exams.
- Less than a fourth (23.3%) had a screening or diagnostic mammogram in the previous year.
- They were three times more likely to have had a mammogram if their doctor recommended one.
Among women 40 to 50 who had received chest radiation for childhood cancer:
- They were more likely to have had mammograms than those aged 25 to 39.
- About two-thirds (76.5%) had a screening mammogram in the past two years (compared with 70% for women who did not receive chest radiation during childhood and 67% for siblings without history of childhood cancer).
- Slightly more than half (52%) had regular breast cancer screenings. (This finding was not significantly higher than those who never had chest radiation.)
- Older women were more likely to undergo breast cancer screening in the past two years or to have received regular screening.
- The chances a woman would report having a mammogram jumped nearly twofold for every five-year increase in age.
"Findings from this study should provide the foundation for targeted interventions involving both clinicians and cancer survivors," the authors conclude.
An accompanying editorial written by doctors in the United Kingdom emphasizes the need for well-designed programs to provide ongoing education for women and their doctors about the risks of breast cancer after childhood chest radiotherapy.
Aliki J. Taylor, MD, PhD, MPH, of the University of Birmingham in Enlgand, and Roger E. Taylor, MD, MA, of Swansea University in Wales also encourage future studies to determine if exposure to radiation during mammography increases the cancer risk for these women, and to explore breast MRI as a possible alternative. They also suggest investigating whether more women in this high-risk group would undergo breast cancer screening if it were provided at no cost.