High-Tech Mammograms Faulted

Computer Systems Don't Detect More Tumors, Study Finds

By Rob Stein
Washington Post Staff Writer
Thursday, April 5, 2007

Computer systems designed to make mammograms more accurate turn out to make them less reliable, according to the largest study to evaluate the increasingly popular high-tech versions of the common test for breast cancer.

The study of more than 429,000 mammograms found that "computer-aided detection" systems did not help radiologists find more tumors and significantly increased the number of false alarms.

The researchers and others said the findings, published in today's issue of the New England Journal of Medicine, show that the expensive systems should undergo more scrutiny.

"The goal of these systems was to make mammography better," said Joshua J. Fenton of the University of California at Davis, who led the study. "Our study suggests that, if anything, they appear to be doing more harm than good."

The study highlighted how new, more expensive technologies can proliferate before enough research has been done to evaluate them, Fenton and others said.

"There's a tendency to say the newest technology has got to be better," said Russell Harris of the University of North Carolina at Chapel Hill. "That's not necessarily the way it works. This appears to be an example of that."

The findings are the latest in a flurry of recent developments that have renewed widespread debates about breast cancer screening. The American College of Physicians this week challenged the long-standing recommendation that all women in their 40s undergo mammograms every year or two, saying that the risks may outweigh the benefits for many. Last week, the American Cancer Society recommended for the first time that women at greatest risk of breast cancer have annual MRI scans, triggering similar arguments over that sensitive but expensive technology.

Together, the developments underscore that breast cancer screening remains imperfect. But several experts stressed that they hope the debate will not dissuade women from having the exams, noting that for the first time, fewer women sought mammograms last year than the year before.

"No screening test is perfect," said Robert A. Smith, the society's director of screening. "But we should never lose sight of the fact that mammography is an important tool in reducing the toll of the disease."

Breast cancer strikes more than 212,000 U.S. women each year and kills more than 40,000, making it the second-leading type of cancer and No. 2 cancer killer among women. Proponents of aggressive screening argue that routine mammograms, and MRIs for those at high risk, help reduce the death toll by catching tumors at their earlier, most treatable stage.

Critics, however, question whether aggressive screening produces too many false alarms, resulting in unnecessary repeat exams, biopsies and treatment, as well as causing anxiety, pain and, for some, disfigurement.

Computer-aided detection systems use computer programs to analyze X-ray images, flagging suspicious areas for radiologists to scrutinize. The Food and Drug Administration approved the first system in 1998.

Each system costs about $150,000, and Medicare and many insurance companies to increase their payments to radiologists who use them by $20 per exam to help recoup the costs. (A standard mammogram typically costs $100 to $150.) Perhaps one-third of mammograms are now interpreted using these systems.

The new study marks the first large attempt to assess how well the computer-aided systems work. Researchers evaluated 429,345 mammograms of 222,135 women at 43 centers in Colorado, New Hampshire and Washington state between 1998 and 2002.

Overall, the systems correctly identified which women had tumors and which did not 87.2 percent of the time, compared with 90.2 percent for standard mammograms, the study found. The systems also led to 31 percent more women being called back for more tests and 20 percent more undergoing biopsies, but detected no more cancers.

The researchers estimate that for every additional woman who received a breast cancer diagnosis, 156 had unnecessary additional tests and 14 had unnecessary biopsies.

"It's clearly not doing what we thought it was doing," said Stephen H. Taplin of the National Cancer Institute, who helped conduct the study.

Wide use of the systems would raise the annual cost of mammography by 18 percent, or about $550 million, the researchers calculated.

The systems found more cancers known as ductal carcinoma in situ (DCIS), which tend to be less dangerous, but had no significant impact on the detection of more dangerous "invasive" breast cancers, the researchers noted.

Some experts, however, said that detecting more DCIS can help more women survive.

"They are underplaying the value of detecting DCIS," said Stephen A. Feig, a professor of radiology at the University of California at Irvine. "It's good to find cancer as early as possible. That's been well established."

Feig and others cautioned against dismissing the computer-aided approach, saying results are likely to improve.

"It has to be fine-tuned, but it's an interesting technology that's going to become a lot better," said Carl D'Orsi of Emory University.

http://www.washingtonpost.com/wp-dyn/content/article/2007/04/04/AR20070404024...