Women Who Survive Childhood Cancer Benefit From Earlier Breast Screening

Annual breast cancer screenings can reduce mortality among women who were treated with chest radiotherapy for a childhood cancer. In fact, according to new research, implementing yearly screening as early as age 25 can cut breast cancer deaths by more than half.

In a study published July 7 in the Annals of Internal Medicine, a multi-institution team of investigators compared the benefits, harms, and cost effectiveness of various breast cancer screening strategies among women who survived a childhood cancer. The study, funded by the U.S. National Institutes of Health and the American Cancer Society, is the first to provide a benefit-harm ratio estimate for this patient group.

The analysis from the team, led by Jennifer Yeh, Ph.D., an associate scientific research in the general pediatrics division in Boston Children’s Hospital, supports the recommendation from the Children’s Oncology Group (COG) – women who have previously undergone chest radiation benefit from having annual mammography or breast MRI screening starting at age 25.

“Our findings underscore the importance of making sure that young women previously treated with chest radiation are informed about their elevated breast cancer risk and the benefits of routine screening,” the team wrote. “Both primary care providers and oncologists who care for survivors should discuss breast cancer screening with these patients.”

According to existing research, there are 55,000 women who received chest radiotherapy at doses of 20 Gy or more to treat a pediatric cancer. Approximately 30 percent of this group will develop breast cancer by age 50 – a rate similar to women with the BRAC1 mutation.

Shown are estimates for the reduction in breast cancer deaths for each screening strategy, by method (mammography with MRI or MRI only) and starting age (25, 30, or 35 years), compared with no screening. G-E = Georgetown University Medical Center and Albert Einstein College of Medicine; Mammo = mammography; MRI = magnetic resonance imaging; W = University of Wisconsin–Madison. Courtesy: Annals of Internal Medicine

To determine what breast cancer screening options offered the greatest benefit, the researchers examined data from two established breast cancer models from the Childhood Cancer Survivor Study and the Cancer Intervention and Surveillance Modeling Network. Using the models, they evaluated three strategies:

• No screening
• Digital mammography with MRI screening starting at age 25, 30, or 35, continuing to age 74
• MRI-only screening starting at age 25, 30, or 35, continuing to age 74

Overall, women in this group had between a 10-percent and 11-percent lifetime risk of dying from breast cancer, and the authors determined that all of the annual screening strategies truncate that mortality rate by more than 50 percent.

Specifically, though, an annual mammogram paired with breast MRI starting at age 25 offers a 56-percent to 71-percent drop in mortality. The life-years gained were also significant – the screenings produced a rise from 1,317 to 2,544 per 1,000 women. In addition, the false-positive screening rate and number of benign biopsy results produced a harm-benefit ratio for these childhood cancer survivors that was better than that for women of average breast cancer risk.

But, when taking cost-effectiveness into consideration, the team discovered that delaying the mammography-MRI screening combination to age 30 might lower the cost to the patient. And, the impact on a patient’s quality of life from putting off screening for five years is marginal, they said.

The study did have limitations, however. Because there is a dearth of research on women who are pediatric cancer survivors, the team based its analysis of MRI and mammography performance on research conducted with women who were BRAC1 and BRAC 2 mutation carriers. Additionally, they did not take into account any risk for radiation-induced breast cancer from repeated mammography screening because the risk between the ages of 25 and 39 is small compared to the radiation doses women received during cancer treatment.

Ultimately, the team said, their findings highlight the importance of incorporating breast MRI into screening for these women.

“Identifying effective policies and interventions to reduce barriers to screening should be a priority for policymakers to ensure comprehensive and coordinated care for these high-risk survivors,” they said.