Breast Cancer Screening at 40 Aids Childhood Cancer Survivors Treated Without Chest Radiation

By Lisa Rapaport

August 18, 2021

(Reuters Health) - Early initiation of breast cancer screening, recommended for high-risk women including childhood cancer survivors treated with chest radiation, might also benefit childhood cancer survivors who didn't receive chest radiation, a new study suggests.

Researchers used data from the Childhood Cancer Survivor Study and two Cancer Intervention and Surveillance Modeling Network (CISNET) models to estimate how initiating breast screening at age 40 in childhood cancer survivors treated without chest radiation might impact breast cancer deaths averted, false-positive screening results, benign biopsies, and incremental cost-effectiveness ratios (ICER).

Without early initiation of breast cancer screening, researchers estimated that the childhood cancer survivors treated without chest radiation had a 6.8% to 7.0% lifetime risk of dying from breast cancer. But early initiation of annual mammograms with MRI screening starting between ages 25 and 40 could potentially avoid 52.6% to 64.3% of breast cancer deaths, researchers estimated.

"Recent studies have shown that survivors of childhood cancer who were not previously treated with chest radiation are also at elevated risk for breast cancer," said lead study author Jennifer Yeh, an assistant professor of pediatrics at Harvard Medical School and Boston Children's Hospital.

"As randomized controlled trials are infeasible given the rarity of childhood cancer, we used modeling to understand whether these survivors could also benefit from early initiation of breast cancer screening," Yeh said by email.

When researchers focused on the cost-effectiveness of early screening initiation, they found that screening starting at age 40, but not sooner, had an ICER below the $100,000 per quality-adjusted life-year (QALY) gained cost-effectiveness threshold. Screening at 40 had an ICER per QALY of $27,680 to $44,380, the authors report in the Journal of the National Cancer Institute.

One limitation of the study is that the simulation models were built on data from survivors who were diagnosed with cancer between 1970 and 1986, making it possible the results don't reflect more modern treatment options.

In addition, many childhood cancer survivors in the study were treated with anthracyclines, and researchers were unable to distinguish between breast cancer risk due to genetic factors as opposed to treatment effects.

Survivors of leukemia and sarcoma have a 4- to 6-fold higher risk of developing breast cancer than the general population, noted Dejana Braithwaite, associate director for population sciences at the University of Florida Health Cancer Center in Gainesville.

"One of the drivers of this increase in risk is exposure to specific chemotherapies, including anthracyclines," Braithwaite, who wasn't involved in the study, said by email.

Clinicians should be aware that childhood cancer survivors who did not have radiation therapy are still at increased risk for breast cancer, and that beginning screening at age 40 is more clearly beneficial and less of a preference-sensitive decision, said Dr. Deborah Korenstein chief of the general internal medicine service at Memorial Sloan Kettering Cancer Center in New York City.

"In addition, although these patients might now meet some current criteria for MRI as a screening tool, they likely benefit from the combination of MRI and mammography," Dr. Korenstein, who wasn't involved in the study, said by email. "However, initiating screening before age 40 is unlikely to be beneficial and may actually cause net harm."

SOURCE: https://bit.ly/2W7djFO Journal of the National Cancer Institute, online July 29, 2021.

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