Using MRI to detect breast cancer in the other breast

This study wanted to find out what traits make a woman more likely to have breast cancer in both breasts, which is too small to be detected by a mammogram. The study found that by doing MRI scans, it is possible to find breast cancer in both breasts, usually in older women with early stage hormone receptor positive cancer.

Breast cancer may have receptors on the tumor that are responsive to treatment. These are called ER/PR and HER2. Magnetic resonance imaging (MRI) is a scan used to see inside the body. It is often used to find cancers that are not able to be found in other ways. An MRI can usually detect breast cancers that a mammogram cannot. It is possible in some patients that breast cancer can be found in both breasts at the same time. This is called synchronous contralateral breast cancer (synchronous CBC). Sometimes the cancer on one side is too small to be seen by a mammogram. It is not known what traits make it more likely for a patient to have CBC.

This study looked back on results from five years of MRI scanning in patients with breast cancer. In this study, 1894 patients had MRI scans. Of these, 60 patients (3.2%) were found to have synchronous CBC.  

There were common traits about the types of cancer that were found. Of the 60 synchronous CBCs, 85% were stage 0 or stage 1A breast cancers. It was found that 95% were hormone receptor positive cancers. 90% of the cancers were HER2 negative. Women more likely to be diagnosed with synchronous CBC were older.

The study found that women more likely to have synchronous CBC detected by MRI were older, and the cancer tended to be early stage and hormone receptor positive.

This was quite a small study. Finding synchronous CBC is rare, so it would be difficult to have a larger study.

Discuss with your doctor the possibility of a MRI before surgery.