Among women with ATM, CHEK2, or PALB2 pathogenic variants, annual MRI screening beginning at age 30 or 35, followed by concomitant MRI and mammography at age 40, could significantly reduce breast cancer mortality, according to a new model.
ATM, CHEK2, and PALB2 are the most common of a more recently discovered group of pathogenic variants that confer a moderate to high risk of breast cancer.
In a study published online Feb. 17, 2022, in JAMA Oncology, researchers used two simulation models and risk estimates from the Cancer Risk Estimates Related to Susceptibility Consortium to predict that MRI screening at age 35 would produce a 54.4%-57.6% reduction in breast cancer mortality, with an estimated 4,661-5,001 false positive screenings and 1,280-1,368 benign biopsies per 1,000 women. At age 30, the model predicted 55.4-59.5% reduction in risk, 5,075-5,415 false positives, and 1,439-1,528 benign biopsies. Annual mammography at age 40 alone could reduce risk by 36%-39%.
The false positives and benign biopsies represent cumulative lifetime results.
“We’ve known for a long time that mammography is less sensitive in younger women than in older women and, of course, when women have a genetic predisposition, we’re very concerned about early-onset cancer. We’ve also known that when you do MRI at the same time as mammography, you find a lot more cancers. [There are] more false positives, but there is clearly a greater yield of cancer in that setting, and the cancers are found earlier,” senior author Mark Robson, MD, said in an interview.
The model showed that mammography screening in women under 40 added no survival benefit, and led to additional false positives and benign biopsies.
“We know that MRI’s detection rate for cancers in a head-to-head comparison with mammography is extremely high, and so I’m not surprised that there was such a difference from a mammography strategy. What I was excited by is just how impactful the MRI screen was in terms of projected reduction in the risk of death. I thought that great,” said Dr. Robson, who is chief of the breast medicine service at Memorial Sloan Kettering Cancer Center, New York.
The balance of mortality reduction versus false positives and benign biopsies will need to be weighed by others. “We didn’t feel like we could make those judgments, but what we were presenting was for people who do make these kinds of policies. The reason that we said 30-35 years (for MRI initiation) is because at that point, the false positive versus life-years gained curve starts to plateau. For instance, when we look at strategies of starting MRI at 25, you we don’t get significantly more life years gained, but we do get more false positives,” Dr. Robson said.
The researchers did not conduct a former cost-benefit analysis for initiating MRI screening at age 30-35.
The study “reinforces the value of MRI for women with these variants that are really just entering the clinical consciousness, and affirms that we need to be doing that in young women to help prevent death from breast cancer. I also think that we need to look at really what mammogram is adding in young women and consider whether or not we really need it at the policy level,” he said.
The study was funded by the National Cancer Institute and the Breast Cancer Research Foundation. Dr. Robson has conducted clinical trials with AstraZeneca, Merck, and Pfizer.