Jun 10 2004
While new technologies hold promise for increasing the accuracy of breast cancer detection, improving access to mammography and broadening the pool of medical personnel who can interpret mammograms offer the greatest potential for immediately reducing the number of lives lost to breast cancer in the United States, says a new report from the Institute of Medicine and National Research Council of the National Academies.
"There is a suite of new devices under evaluation -- such as ultrasound and computer-aided detection (CAD) -- that should make early detection even more effective in the future, although improvements in the next few years are likely to be incremental rather than revolutionary," said committee chair Edward Penhoet, director of science and higher education programs, Gordon and Betty Moore Foundation, San Francisco, and former dean, School of Public Health, University of California, Berkeley.
New technologies based on protein or gene profiling hold promise for providing more personalized screenings and identifying women at greatest risk for breast cancer. However, it remains to be shown whether these technologies will yield results that are reliable enough to be useful in the early detection of breast cancer, said the committee that wrote the report. "In the meantime, because current mammography technology is good but imperfect, and because there are many barriers hindering access to mammography, too many women will die from breast cancer this year," Penhoet said. "Improving and increasing the use of current mammography technology is the most effective strategy we have right now for further reducing the toll of breast cancer."
More than 200,000 new cases of breast cancer will be diagnosed this year, and more than 40,000 women will die from the disease. One of the biggest problems facing women today is that their access to breast cancer screening is endangered due to a shortage of breast imaging specialists, the report says. Each year, more than 1.2 million American women turn 40, the age when most are recommended to get their first mammogram, but there are not enough breast imaging specialists to keep up with the demand. Fewer radiologists are going into breast imaging because of heavy regulation, fear of lawsuits, and low reimbursement for long hours. At the same time, mammography facilities are closing faster than new ones are opening. Between 2000 and 2003, the number of mammography facilities operating in the United States has dropped from 9,400 to 8,600 -- an 8.5 percent decrease. As a result, women are being made to wait up to five months for mammograms in some areas, the report notes.
Studies in the United Kingdom show that trained nonphysician health care professionals can interpret results with the same accuracy and speed as radiologists. Given the failure of the U.S. health care system to keep pace with the growing demand for mammography, the committee recommended that mammography facilities should enlist specially trained nonphysician personnel to pre-screen or double-read mammograms to expand screening facilities' capacity. Nonphysician personnel would not make diagnoses, and every mammogram would be independently viewed by a breast imaging specialist.
To improve the quality of cancer screening, the United States should adopt elements of screening programs that have proved successful in Sweden, the Netherlands, and the United Kingdom, which have lower rates of false-positive results, the committee said. It estimated that reducing the number of false positives could cut the costs related to additional testing by $100 million a year because approximately 200,000 fewer women would be called back for follow-up work. The United States also should consider such practices as requiring double readings of mammograms, interpretation of mammograms in high-volume centers, and screening services that also integrate treatment, counseling, and other support services.
Tests are under way to assess the clinical value of ways to refine screening strategies for high-risk women and to improve the accuracy of mammographic interpretations. These methods include digital mammography, CAD, ultrasound, and magnetic resonance imaging. The committee encourages the validation and integration of new technologies into breast cancer screening because current mammography is imperfect and does not work equally well in all women. Mammography correctly flags undetected cancers 83 percent to 95 percent of the time, but this means that up to 17 percent of tumors go undetected. Moreover, the chance of a false-positive result from a traditional mammogram is about 1 in 10.
The report notes that research and discovery phases of new technology development are proceeding well. The weak link in development is the phase in which technologies are shown to improve health outcomes and that they can be used effectively in routine clinical practice. Many cancer detection technologies that have been proposed and developed over the years have proved to be of no value to patients or medical practice, the committee noted. It urged that more attention be paid to validating technologies and building a more robust system for assessing whether they will be useful in clinical practice. Organizations that fund breast cancer research, such as the National Institutes of Health, Department of Defense, and private foundations, should support research on how best to evaluate and apply new screening and detection technologies.
Because there is so much individual variation in susceptibility to breast cancer, more refined screening strategies should be developed, the report says. Screening based on individualized genetic risk profiles for women will substantially improve early detection efforts, the report says. However, more research is needed on genetic risk factors before these biologically based technologies can be used fully to tailor detection strategies.
In addition, the actual risks of developing breast cancer need to be better communicated to women so that they can make informed decisions about screening and their lifestyle. Surveys show that older women are more likely to underestimate their risk than younger women, and that younger women tend to overestimate their risk. The National Cancer Institute, private foundations, and others should develop better tools for communicating risk to help health care providers discuss breast cancer risk more effectively with patients and the media.
The new report, Saving Women's Lives: Strategies for Improving the Early Detection and Diagnosis of Breast Cancer,expands on the work of a previous IOM and NRC committee that a few years ago examined the array of promising detection and diagnostic technologies under development. That committee's report, Mammography and Beyond: Developing Technologies for Early Detection of Breast Cancer,published in 2001, concluded that mammography -- despite its problems -- was still the best choice for screening the general population to detect breast cancer at early and treatable stages.
The new report was sponsored by the Breast Cancer Research Foundation, National Cancer Institute, Apex Foundation, Josiah H. Macy Jr. Kansas Health Foundation, Carl J. Herzog Foundation, Mr. Corbin Gwaltney, and Mr. John Castle. The Institute of Medicine and the National Research Council are private, nonprofit institutions that provide science and health policy advice under a congressional charter. A committee roster follows.