TOPLINE:

New data suggested that regular magnetic resonance surveillance (MRI) surveillance lowers the risk for breast cancer mortality by 80% in women with BRCA1 sequence variations, but the benefits of MRI surveillance did not appear to extend to women with BRCA2 sequence variations.

METHODOLOGY:

• The National Comprehensive Cancer Network Clinical Practice Guidelines recommend women at high risk for breast cancer, such as those with BRCA1 or BRCA2 gene mutations, receive a mammogram as well as a breast MRI every year, starting as early as age 25 years.
• In this study, researchers compared the breast cancer mortality rates among women with BRCA1 or BRCA2 sequence variation who did vs did not receive annual breast MRI screening.
• The team evaluated 2004 women with BRCA1 and 484 with BRCA2 sequence variations from 59 centers in 11 countries, including the United States, Canada, Poland, Norway, Israel, Italy, and the Bahamas; 1756 (70.6%) of these women had at least one screening MRI and 732 women (29.4%) did not.
• Participants completed a baseline questionnaire at enrollment as well as subsequent follow-up questionnaires every 2 years, which collected information on surgeries, hormone use, and participation in MRI surveillance programs.
• The primary endpoint was breast cancer-specific survival.

TAKEAWAY:

• During a mean follow-up of 9.2 years, there were 241 breast cancers and 14 deaths from breast cancer among 1756 women in the MRI surveillance group and 103 breast cancer cases and 21 breast cancer-related deaths in women who did not undergo MRI surveillance.
• MRI surveillance reduced the risk for breast cancer-related deaths by 80% among women with BRCA1 sequence variations (hazard ratio [HR], 0.20; P < .001) but not in those with BRCA2 sequence variations (HR, 0.87; 95% CI, 0.10-17.25; P = .93).
• The 20-year cumulative risk for breast cancer mortality was 14.9% in women who did not undergo MRI surveillance and 3.2% in those undergoing MRI surveillance.
• In women diagnosed with invasive cancer, 10-year survival was 93.8% in the MRI group vs 86.7% in the no-MRI surveillance group (P < .01).

IN PRACTICE:

“It is time to put these results to work saving lives” to identify BRCA1/2 carriers and encourage regular MRI surveillance, experts wrote in an accompanying editorial. The editorialists also noted longer follow-ups are needed to determine MRI surveillance benefits in BRCA2-positive women.

SOURCE:

This study, led by Jan Lubinski from Pomeranian Medical University, Szczecin, Poland, was published in JAMA Oncology on February 29, 2024.

LIMITATIONS:

The study had a short follow-up of 9.2 years on average; ideally women should be followed up until age 75 years to establish the lifetime risks of breast cancer. The screening MRI exams took place over more than two decades, from 1997 to 2018, and may not reflect current protocols.

DISCLOSURES:

This study was supported by the Canadian Institutes of Health Research, the Peter Gilgan Centre for Women’s Cancers at Women’s College Hospital, and the Canadian Cancer Society. The authors reported financial relationships outside this work.