Postmenopausal women, including those over 70 years old, who have been newly diagnosed with cancer in one breast have higher cancer detection rates when the other breast is scanned for tumors with MRI, compared to premenopausal women, say researchers at the Mayo Clinic campus in Florida.
They found 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.
Of particular interest to the researchers is their finding that 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.
"Our findings are not really surprising because we know that the risk of breast cancer increases as age increases," says the study's lead investigator, Johnny Ray Bernard Jr., M.D., a Radiation Oncologist at Mayo Clinic in Jacksonville. "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."
Since 2003, Mayo Clinic in Jacksonville has offered MRI imaging of both breasts in women with newly diagnosed 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. Contralateral refers to the opposite breast where cancer was not diagnosed.
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.
The researchers undertook the study, they say, because to their knowledge, no published studies in the medical literature that have examined the use of MRI to screen contralateral breasts in women diagnosed with breast cancer have included an analysis of women 70 and older.