June 16, 2003 -- Follow-up breast cancer screening using magnetic resonance imaging (MRI) can track and catch some of the smallest, early breast cancers in high-risk women while they are most susceptible to treatment. A new study shows follow-up MRI can detect curable early breast cancers that cannot be found by mammography or physical exam.
Researchers say the study, published in the July 15 issue of Cancer, is the first to examine "probably benign" findings from MRI breast cancer screening among women at high risk of developing breast cancer due to a family history of the disease or previous breast cancers.
Although breast cancer screening using MRI is very good at picking up the tiniest abnormalities in the breast, it can also pick up benign or normal growths in breast tissue. Researchers say MRI screening is less accurate at determining which of these growths may be cancerous, and the outcome of probably benign growths detected by MRI has not been studied until now.
Tracking Early Breast Cancers With MRI
In this study, researchers followed 367 women at high risk for developing breast cancer who had normal mammograms and were referred for further screening using MRI.
Follow-up breast cancer screening using MRI is frequently recommended for tracking growths or abnormalities in the breast that doctors believe are probably noncancerous or benign. Researchers say breast cancer screening has several advantages over biopsy in this regard because it is noninvasive, less expensive, and causes less anxiety for the patient than biopsies, which require removal of breast tissue with a needle for further testing.
Breast cancer screening using MRI found "probably benign" growths in 89 of these women (24%). Follow-up MRI screening was performed for 79% of these women after an average of 11 months. Most of the women who were referred for follow-up MRI had multiple growths, usually in both breasts.
Twenty of the 89 women subsequently had a biopsy after follow-up MRI due to progression of the growth. Breast cancer was found in nine women. This means that approximately 10% of the women initially diagnosed with probably benign growths had early breast cancer.
Many Respond to Treatment
Researchers say more than half of the breast cancers found were ductal carcinoma in situ (DCIS), a type of cancer that responds well to treatment when caught in the early stages.
The study also found more than half of the breast cancers identified were detected by MRI alone, not by conventional methods.
"These data indicate that follow-up breast MR imaging in high-risk women can detect early breast [cancer] before it can be diagnosed by mammography or physical examination," write researcher Laura Liberman, MD, and colleagues at the department of radiology at Memorial Sloan-Kettering Cancer Center in New York City.
Researchers say more study is needed among larger groups of women to determine the most appropriate intervals for follow-up breast imaging using MRI. MRI breast screening is currently recommended only for women at high risk for breast cancer because it is relatively new and significantly more expensive than traditional mammography screening.