In diagnostic performance, the recall rate – the percentage recalled for additional testing – was 9.3% (60 of 646) in the personal history group, significantly lower than the 15.0% (49 of 327) in the genetic or family history group.
The positive predictive value of biopsy – the percentage found to be malignant – in the personal history group was 35.7% (20 of 56), significantly higher than in the genetic and family history group (12.2%, or 5 of 41). The cancer yield – the fraction of all women screened who were found to have a malignancy – was 3.1% (20 of 646) in the personal history group, or more than twice the 1.5% (5 of 327) found in the genetic and family history group (P =.14). The sensitivity was 90.9% (20 of 22) in the personal history group (which had two false negatives not found with breast MRI) vs. 100% (5 of 5) in the genetic and family history group. Specificity was 93.6% (584 of 624) in the personal history group, higher than the genetic and family history group’s 86.3% (278 of 322).
The date of original cancer was available for 18 of the 20 malignancies detected by MRI, and 11 of the 18 were detected greater than 5 years after the original cancer.
“The diagnostic performance of screening breast MRI was similar to or higher overall in women with personal history alone compared to those with a genetic or family history,” said Dr. DeMartini. “Women with a personal history of breast cancer had a lower recall rate, higher positive predictive value, higher cancer yield (although not statistically significant) and higher specificity.”
Screening breast MRI may therefore be an important adjunct to mammography in women with a personal history of breast cancer, she said, and should be a step in the direction of evidence-based, personalized surveillance of women who are breast cancer survivors.
Asked later at a news conference whether other prospective studies were underway, Dr. DeMartini said that to her knowledge there were not. However she now recommends to her own patients, “that they strongly consider breast MRI and discuss it with their provider.” Dr. DeMartini said that the typical cost of breast MRI is between $1,000 and $2,000.