The study included 27,274 screening mammograms done over a three year period---19,402 were done using a computer-aided mammography detection system (CAD); 7,872 were mammography studies done before the CAD system was installed, said Tommy E. Cupples, MD of ImageCare, LLC in Columbia, SC, and the lead author of the study. The study was conducted at the South Carolina Comprehensive Breast Center.
"Overall, we saw a 16% increase in the cancer detection rate," said Dr. Cupples, but the increased detection rate doesn't tell the whole story, he said. "The more important question is do we find more cancers earlier, when they are smaller and most curable." CAD increased the detection rate of small invasive cancers (those 1 cm or less) by 164%, said Dr. Cupples. "Invasive, lump forming cancers are more likely to be lethal if they aren't detected early, especially in younger women," he said. "The average ages of mammography screening detected cancers in the CAD group was more than five years younger than in the pre-CAD group," Dr. Cupples said.
In the study, the radiologists reviewed each mammogram and then activated the CAD system. The CAD system "marked" areas on the mammogram that were suspicious for cancer, then the radiologists would again review the mammogram. "The CAD system we used was particularly useful for finding small masses," said Dr. Cupples. "Small masses are difficult for radiologists to detect, especially in younger women with denser breast tissue. The CAD system is an excellent addition to the radiologist's expertise," he said.
The recall rate – the rate at which patients were called back for additional studies or a biopsy -- was 7.71% in the pre-CAD group and 8.34% in the CAD group. A recall rate of less than 10% is considered to be acceptable, Dr. Cupples said. The biopsy rate increased from 1.37% in the pre-CAD period to 1.47% in the CAD period. "The increase in the detection of smaller cancers more than made up for the increase in the recall and biopsy rate," Dr. Cupples said.
The study appears in the October 2005 issue of the American Journal of Roentgenology.
The American Roentgen Ray Society (ARRS) was founded in 1900 and is the first and oldest radiology society in the U.S. The ARRS is named after Wilhelm Röentgen who discovered the x-ray in 1895. For more information, visit www.arrs.org.
Journal
American Journal of Roentgenology