Computer System Helps Locate Breast Cancer
A new computer system to help radiologists double-check mammograms, approved late last month by the Food and Drug Administration, is not yet available in Southern California, but is expected to be in place here before the end of the year.
The FDA estimates that the ImageChecker, made by R2 Technology Inc. of Los Altos, Calif., could improve radiologists’ detection rates from 80 of 100 breast cancers, now typically found, to 88 of 100. Data from clinical studies conducted by R2, in which more than 40,000 mammograms were evaluated, were submitted to the FDA.
The ImageChecker works by scanning a conventional mammogram with a laser beam, converting the image into a digital file, says Alan Stein, R2 Technology’s vice president of regulatory affairs. “It’s run through the ImageChecker processor, which is somewhat like a spell-checker on your computer. The processor identifies features in the film that have characteristics associated with cancer. Two small monitors then display areas to be double-checked.” The process takes about four minutes.
The radiologist looks at the suspicious areas highlighted on the monitors, then reviews the same areas on the original mammogram to determine if further evaluation is needed.
In a company study of 1,083 women with breast cancer, the investigators collected all available prior mammograms and asked five independent radiologists to look at the films. “The majority found that 15% of the cases could have been caught earlier,” Stein says. Then the ImageChecker was used on all the prior films. “And the ImageChecker marked 85% of those cases that should have been caught sooner.”
About 180,000 new breast cancer cases will be diagnosed in the United States this year, the American Cancer Society estimates, and about 44,000 patients are expected to die this year of the disease.
Stein says his company is in discussions with several Southern California hospitals, health maintenance organizations and radiologists interested in purchasing the system, which costs $175,000. In a high-volume center performing about 10,000 mammograms a year, Stein estimates that the ImageChecker would add about $5 to the cost of each one, but fees would be determined by individual health centers.
In the U.S., the cost of a mammogram ranges from $40 to $150. If a woman’s mammogram is done at a facility that does not have ImageChecker, it’s feasible to take it to a center that does have the system for a double-check, Stein says, but whether a center would offer the ImageChecker service to patients whose mammograms were taken at other clinics and what they would charge would be determined by each center.
Dr. Lawrence W. Bassett, Iris Cantor professor of breast imaging at UCLA, says that computer-assisted detection, also under study by other researchers, shows promise, but needs work. “It has the potential to improve the detection of breast cancer, but it has potential adverse consequences,” he says. An example, he says, is “if nonexperts use it and recommend an unnecessary biopsy for subtle abnormalities that an experienced radiologist would have correctly called normal tissue.
“Computer-assisted detection will be a more feasible tool when we have digital mammography,” Bassett says. With digital mammography (rather than conventional film mammography), the computer-assisted detection techniques won’t require digitization of film images to provide readable input for the computer.
Digital mammography is expected to be on the market within one or two years and will probably be phased in gradually due to the expense of the new equipment.
