March 10, 2010 - Postmenopausal women, including those over 70 years old, who have been newly diagnosed with cancer in one breast have higher cancer detection rates compared to premenopausal women, according to research conducted at the Mayo Clinic campus in Florida.
Researchers at the Mayo Clinic used magnetic resonance imaging (MRI) to find that 3.8 percent of 425 women had breast cancer in the undiagnosed breast that had not been found with a clinical or mammographic examination; all were postmenopausal. In these women, detecting and treating cancer in both breasts at the same time may save costs, patient stress, and the potential toxicity that may come from having to treat cancer later in the second breast once it is discovered, the researchers say in the March/April issue of The Breast Journal.
They also found patients 70 and older had a higher prevalence of cancer detected in the second breast by MRI than did younger patients in the study. MRI detected a cancer in the second breast in 5.4 percent of 129 elderly women included in the study.
Lead investigator, Johnny Ray Bernard Jr., M.D., a radiation oncologist at Mayo Clinic in Jacksonville noted, "Elderly women in good health potentially benefit from earlier detection, and we believe that screening of the undiagnosed breast with MRI should be considered in all postmenopausal women diagnosed with a breast cancer."
In this study, Mayo researchers retrospectively reviewed the records of 425 women who underwent bilateral breast MRI between 2003 and 2007. The goal was to determine the prevalence of "contralateral" cancer detected by MRI, but not found by mammogram or clinical breast exams. They concluded that postmenopausal status was the only statistically significant predictor of contralateral cancer detected by MRI.
In 72 of the 425 women, MRI detected a suspicious lesion. A follow-up biopsy showed that 16 (22 percent) of the 72 women had contralateral breast cancer (stage 0-1) that had not been detected with typical screening methods. Of the 16 women diagnosed with a contralateral cancer, seven were 70 or older.
This is the first published study in the medical literature examining the use of MRI to screen contralateral breasts in women diagnosed with breast cancer that has included an analysis of women 70 and older. Studies have shown that MRI of the breast has a higher cancer detection rate than clinical breast examination and mammography alone in women at high risk for developing breast cancer. Additionally, women who have been diagnosed with breast cancer are at 2-to-6 times increased risk for developing a secondary, contralateral breast cancer, compared to women at average risk. Dr. Bernard believes that the combination of older age and a personal breast cancer history possibly makes women aged 70 years or older with newly diagnosed breast cancer at even higher risk for developing a contralateral breast cancer.
Dr. Bernard suggests these findings may help clarify the debate over whether to do routine use of breast MRI in all patients with a history of breast cancer at initial diagnosis because it suggests that postmenopausal patients have the highest prevalence of contralateral breast cancer identified only by MRI, and not by mammogram or physical examination.
The researchers concluded that limiting screening MRI to those groups likely to have higher detection rates, such as postmenopausal women in our study, could reduce costs by having both cancers treated at the same time instead of undergoing potentially toxic and expensive treatments twice.
For more information: www.mayoclinic.org/breast-cancer