AJR: Pre-op breast MRI helps detect occult cancers
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| Breast MRI Navigation software Image source: Sentinelle Medical |
Although the use of breast MRI has been accepted as a high-risk screening tool, its role among newly diagnosed patients has not yet been established. Some studies have suggested that breast MRI delivers high sensitivity in the detection of occult breast cancers among newly diagnosed patients, but critics protest that the results may not be generalizable.
Researchers from the breast imaging section at the University of Washington Medical Center and Seattle Cancer Care Alliance, both in Seattle, undertook a retrospective review of all breast MRI studies performed between Jan. 1, 2003 and April 30, 2007. The study team prospectively analyzed the breast MRI studies of 570 women and recorded patient age, breast density, index tumor histology, receptor status and lymph node status. They also calculated biopsy rates, positive predictive values of biopsy and overall cancer yield across various parameters.
Twenty-seven percent of the patients underwent imaging-guided core needle biopsy or surgical excision for one or more suspicious lesions detected by MRI, reported lead author Robert L. Gutierrez, MD, from the department of radiology at Seattle Cancer Care Alliance. Physicians located additional cancer sites in 67 of the 152 women referred for biopsy, producing a positive predictive value of 44 percent.
Gutierrez and colleagues also found that 12 percent of women in the study had otherwise occult cancers diagnosed by MRI alone.
“Our data add to the growing body of literature that documents the ability of preoperative breast MRI to detect otherwise occult additional diseases among women with newly diagnosed breast cancer,” summed the researchers. What’s more, the researchers pointed out that the additional cancer yield of 12 percent in this study significantly exceeds the widely accepted added cancer yield of 0.08 to 6.7 percent for high-risk screening breast MRI.
Gutierrez and colleagues offered that a major strength of the study was its focus on a broad population that represented the patient age and histology of newly diagnosed breast cancer patients across the U.S. However, they acknowledged the limits of a single-site, retrospective design, which was somewhat counterbalanced by a prospective review of all data.
Although the study population reflected the larger U.S. population, the researchers noted that it did take place in at an academic medical center, and the performance of breast imagers and surgeons may differ from those in other settings.
Gutierrez and colleagues also noted the lack of documented mortality benefit and the lack of evidence regarding improved surgical outcomes associated with breast MRI and suggested that future research focus on surgical outcomes.