MRI finds earlier breast cancers in gene carriers

Breast cancer screening that includes MRI scans may reduce the chance of finding advanced cancer in women at high genetic risk of the disease, a new study suggests.

That's because MRI appears to discover their breast cancers at an earlier stage. Whether this means women in the high-risk group will live longer isn't clear yet, however.

"I think the main take-home message for women is that there are choices, and we have data to support them," said Dr. Monika L. Burness of the University of Chicago in Illinois, who co-authored an editorial published with the study.

The study, reported in the Journal of Clinical Oncology, followed women with mutations in the BRCA1 or BRCA2 genes that put them at a much higher than average risk of developing breast or ovarian cancer.

The National Cancer Institute estimates that about 60 of every 100 women with these gene mutations will develop breast cancer over their lifetime - versus around 12 of every 100 women in the general population.

For women at average risk of breast cancer, experts recommend breast cancer screening with mammograms. But because MRI can pick up smaller tumors, the American Cancer Society advises that women with BRCA mutations be screened with both mammography and MRI.

Until now, though, it had not been clear whether MRI can reduce their risk of being diagnosed with advanced cancer.

The new study looked at how far advanced the breast tumors were when they were discovered.

About a third of the women had yearly breast cancer screening that included MRI scans. Two of every 100 women in this group were diagnosed with stage 2 to stage 4 breast cancer. In the remaining two-thirds of the study participants, who had mammograms but not MRI, such higher-stage tumors were discovered in 7 of every 100 women.

In stage 2 breast cancer, the tumor is either relatively large or has spread to nearby lymph nodes; by stage 4, the cancer has spread to distant sites in the body.

Yearly screening is not the only way for women with BRCA mutations to manage their increased risk. They can also have preventive mastectomy - surgical removal of healthy breasts - to cut their odds of breast cancer. Two drugs, tamoxifen and raloxifene, may also be able to reduce the risk.

A study published last year in the Journal of the American Medical Association found that of nearly 2,500 women with BRCA mutations, no one who had a preventive mastectomy developed breast cancer in the next three years, compared to 7 of every 100 women who did not have the surgery.

While MRI often finds breast cancers earlier, when they're curable, according to editorial author Burness, it's not clear exactly how MRI screening measures up against preventive mastectomy in the long term.

However, she told Reuters Health, the current findings underscore the fact that women with BRCA mutations have options for managing their risk. And screening with MRI is "a reasonable alternative to preventive surgery," Burness said.