A study in the Journal of the American Medical Association examined more than 2600 women with an elevated cancer risk and dense breasts. The women underwent three yearly mammogram and ultrasound screenings. In the third year of the study, around 700 women received a single screening MRI.
"About half of the cancers were found on mammography. If we added ultrasound, there was another essentially third of the cancers that were seen only on ultrasound. The vast majority of those cancers were invasive and were node negative, which again are the most important cancers for us to find on screening," said one of the study co-authors, Dr. Wendie Berg of the University of Pittsburgh School of Medicine.
According to Dr. Berg, "adding MRI i was probably not necessary for the vast majority of the women in our study because we still were able to find cancer before it was a lump by just the combination of ultrasound and mammography in most of our patients."
Researchers say having an MRI or ultrasound also carries a higher risk of false positive results, extra follow-up testing and biopsies. Only 58% of women in the study who were offered a screening MRI underwent the proced