Routine use of computer-aided detection (CAD) in interpretation of screening mammograms is as beneficial as having a second radiologist review the mammograms, a new prospective study shows. CAD improves the cancer detection rate, but does not dramatically increase the patient recall rate.

A prospective study of 4,341 consecutive screening mammograms found that CAD increases the cancer detection rate by 5.4%, said Priscilla Slanetz, MD, MPH, director of breast imaging at Caritas St. Elizabeth's Medical Center, Boston, MA, a teaching affiliate of Tufts University School of Medicine.

"This number is probably lower than what other facilities might see because the radiologists reading the images at our facility are very experienced. Because they are experienced mammographers they are less likely to miss cancers that are then picked up by CAD," said Slanetz. Previous studies have shown that double reading (having a second radiologist review the mammograms) picks up between 5% and 15% more cancers, she noted.

The study found that CAD missed 11 of 38 cancers, particularly those that presented as architectural distortion or those that were asymmetric and low in x-ray attenuation; however, CAD was very precise in detecting calcifications, said Slanetz. The radiologists missed two cases of faint calcifications that were detected by CAD. One cancer case was missed by both, said Slanetz.

The recall rate (the chance that a screening patient is called back for additional imaging evaluation) went from 11.5% without CAD to 13.4% with CAD, said Slanetz. This is not a significant increase, she added.

The results of this study indicate that CAD is an effective way to double-read mammograms without the need for a second radiologist. This is especially important since the demand for mammography continues to increase (more and more women are being screened as the baby boomers age), while there is a decrease in manpower (An increase in mammography related lawsuits are at least partly responsible for the decrease in the number of people interested in becoming breast imagers, said Slanetz.)

This is only the second prospective study done on CAD; numerous retrospective studies have shown the effectiveness of CAD, Slanetz added. The study was presented at the American Roentgen Ray Society Annual Meeting in Miami Beach, FL.

SOURCE:
Annual Meeting of the American Roentgen Ray Society, May 4, 2004, Miami Beach, FL
American Roentgen Ray Society (http://www.arrs.org)