Impact of Breast MRI on Surgical Decision Making Examined
A new report published in the Annals of Oncology by a Dutch research team indicates that use of magnetic resonance imaging among women at high-risk of developing breast cancer has a high incidence of false positives. Alternatively, this type of imaging is more effective than mammography in detecting invasive cancers. They further noted the impact of ongoing surveillance with mammography and MRI on decision-making regarding prophylactic mastectomy.
Annual MRI is recommended in the U.K. as a screening tool for women who have a family history of of breast cancer along with traditional mammography. The benefit of this approach is that it is more sensitive than other imaging tools. The downside of such is that the rate of sensitivity increases the likelihood that irrelevant abnormalities will be detected.
The team recruited 196 women who had either the BRCA1 or BRCA2 mutation. The goal of the trial was to assess the rate of false-positives with MRI. An additional outcome of interest was the impact of results from screening trials on patients’ decisions regarding prophylactic mastectomy. Follow up for this project was continued over two years.
When these women presented to the Cancer Center at the Nijmegen Medical Centre, they were given a variety of options for imaging surveillance. They were also offered the possibility of undergoing bilateral protective mastectomy. These options were presented at the time that women were found to have the genetic mutation associated an increased risk of developing breast cancer.
Almost 30 percent of the women opted to undergo protective mastectomy. Three patients had no preference and the remaining patients chose to have regular check ups. All of the patients did undergo preliminary MRI scans. Findings from 83 percent of the MRI studies indicated an abnormality that was found to be a false-positive.
Following assessment of the scans, approximately 90 percent of the original group that wanted to undergo mastectomy went on to have the procedure completed. Approximately thirty percent of the women who had positive findings from MRI who had opted for surveillance decided to undergo surgery after the MRI findings were revealed.
The researchers determined that the decision to undergo prophylactic mastectomy was most often determined by patient preference prior to undergoing MRI. The findings from MRI appeared to be less influential on this decision-making progress, as well as genetic counseling and other surveillance activities.
Additional findings from the study support the value of MRI as a screening modality for high-risk population. In this group of patients, the rate of true positives was 60 percent with MRI versus 41 percent with mammography. The combined sensitivity of MRI and mammography was 71 percent and 90 percent specificity. The researchers note, in light of such, that MRI screening for high-risk populations still offers important benefits for screening. The Dutch team recommends this assessment in combination with mammography.
April 1, 2008 Related topics: Imaging, Diagnostic, Radiology, Hematology & Oncology