Brain MRI tracks risk of stage IV breast cancer metastases

Brain MRI shows promise for surveilling women at risk for asymptomatic stage IV breast cancer metastases by tracking molecular subtypes of the disease, researchers have reported.

"[We found that the] highest frequency of brain metastases at baseline was in triple-negative and HER2-positive [human epidermal growth factor receptor 2-positive] breast cancer," wrote a team led by Kamran Ahmed, MD, of Moffitt Cancer Center in Tampa, FL. "Following [a] six-month MRI, the cumulative frequency was approximately a quarter across all subtypes." The group's results were published January 24 in Neuro-Oncology.

Screening for asymptomatic stage IV breast cancer using brain MRI is not currently recommended by the National Comprehensive Cancer Network (NCCN), and the incidence of asymptomatic brain metastasis has not been well-tracked, Ahmed and colleagues explained. To address the knowledge gap, the researchers conducted a single-arm, phase II trial to investigate the performance of surveillance brain MRIs to determine the frequency of asymptomatic brain metastasis in metastatic breast cancer in 101 neurologically asymptomatic patients.

To be eligible for the study, the women had to have an Eastern Cooperative Oncology Group (ECOG) score equal to or less than 2 and a life expectancy of at least six months. The patients were categorized into the following cohorts: triple negative (n = 28), HER2-positive (n = 33), and hormone receptor (HR)-positive/HER2-negative (n = 40). All underwent a surveillance brain MRI and a second brain MRI at six months if the initial MRI exam was negative.

The group found the following:

• The overall frequency of brain metastasis on initial surveillance brain MRI was 14%, with rates of 18%, 15%, and 10% in triple-negative, HER2-positive, and HR-positive/HER2-negative patients, respectively.
• On six-month follow-up MRI, cumulative rates of brain metastasis increased to 25% in triple-negative, 24% in HER2-positive, and 23% in HR-positive/HER2-negative patients.

The findings suggest that future research regarding the use of brain MRI for this indication could improve care for these patients, according to the authors.

"These results warrant confirmatory trials to refine brain MRI surveillance recommendations for neurologically asymptomatic stage IV breast cancer," they concluded.

The complete study can be found here.