So says a new report from the Institute of Medicine (IOM) and National Research Council of the National Academies. More evaluation and development of new imaging tools and of promising molecular biological techniques are required and warranted, the report says.

"With all of its limitations, film mammography remains the gold standard against which new imaging technologies will be measured," said Joyce C. Lashof, chair of the committee that wrote the report and professor emerita, School of Public Health, University of California, Berkeley.

She continued, "To date, no quantum leap has been made in this area. At the same time, many of the newer tools offer certain advantages and deserve to be studied further."

In fact, no single imaging technology is capable of accurately detecting all breast abnormalities, the report says. Ultimately, the best detection may come from using several different tools. For example, ultrasound and magnetic resonance imaging (MRI) have shown potential as adjuncts to mammography in diagnosis and screening, especially in getting a clearer picture of dense breast tissue in certain women.

In addition to evaluating scientific evidence on the new technologies, the committee examined the process by which newer screening technologies work their way through the pipeline from testing to routine clinical usage.

The report raises a concern that technologies approved for diagnosis could be prematurely adopted for screening, noting that diagnostic tools help determine the nature of a breast abnormality first detected through screening and may not be appropriate for both purposes.

In evaluating a new technology's appropriateness for screening, the U.S. Food and Drug Administration (FDA) and the Health Care Financing Administration (HCFA) should base approval and coverage decisions on results of clinical trials that prove screening effectiveness, the committee said.

To accomplish this goal, a more systematic approach is needed for the assessment of screening tools, the committee said. Such an approach must involve clinical trials that are coordinated and designed with support and input from relevant federal agencies and breast-cancer advocacy organizations.

Private insurers also should do their part by covering the costs of screening tests for women who participate in clinical trials but are not eligible for Medicare or Medicaid -- government programs that were created to cover health care costs for seniors and for individuals with certain disabilities or limited incomes.

Because detection technologies and treatments are continually evolving, the National Cancer Institute (NCI) should sponsor clinical trials every 10 to 15 years to reassess the effectiveness of established screening tools, the report says.

In addition, since age distribution in the United States is shifting toward an older population, the NCI should collaborate with other organizations in sponsoring further studies to assess the benefits and risks of mammography in women over age 70.

While imaging technologies indicate structural differences or changes in the breast, such as microcalcifications or new growths, some of the latest molecular biological technologies can provide information about the cellular characteristics of these abnormalities -- potentially leading to more accurate screening and diagnosis.

Therefore, the committee also examined a number of tools such as growing breast cancer cells in the lab and identifying the genetic changes in particular kinds of tumors.

To increase understanding of the cellular characteristics of different tumors, researchers need specimens of breast tissue and fluids containing precancerous and cancerous cells. NCI should facilitate expansion of breast cancer specimen banks, both in number and resources, the committee said.

This would aid identification of early-stage abnormalities that could become lethal. Women who contribute specimens for research should be assured confidentiality and protection against genetic discrimination.

Greater public access to current technologies is needed, particularly for women who lack health insurance, the report urges. Congress should expand the Centers for Disease Control and Prevention breast-cancer screening program to reach more women -- from the current 15 percent to 70 percent -- and state legislatures should provide Medicaid funds for treatment of women with breast cancer identified through this screening program.

In addition, the Health Care Financing Administration and a panel of independent experts should analyze the current Medicare and Medicaid reimbursement rates for mammography and comparable radiologic techniques to determine whether the cost is adequately covered.

Federal agencies and professional organizations should evaluate the current and future numbers of radiologic specialists and take measures to ensure an adequate supply of these experts, the report declared.

The committee evaluated imaging tools currently available, examining film mammography and 17 other technologies. These included ones with FDA approval, such as full-field digital mammography, ultrasound, computer-aided detection systems and magnetic resonance imaging, as well as those not yet approved, such as optical imaging.

Many appear to offer varying degrees of potential for screening or diagnosis -- in some cases, both -- but more research is needed, the report says.

No studies have shown a new technology to be a replacement for film mammography, for screening or for diagnosis. For instance, while digital mammography has been lauded as a major technical advance -- facilitating storage, retrieval, transmission and image adjustment for mammograms -- it has not shown greater accuracy than its nondigital counterpart.

There are multiple reasons for the push to develop new imaging and diagnostic technologies. Among women in the United States, the death rate from breast cancer has been decreasing by about 2 percent annually over the past decade, suggesting that early detection and improved therapy are having an impact on the disease, the report says.

Despite these optimistic findings, the fact remains that film mammography does not detect all cancers, particularly among younger women, who often have denser breast tissue that is more difficult to view with X-ray technology.

Film mammography also cannot prevent all deaths from breast cancer because it may not detect fast-growing malignancies early enough to effect a cure. Routine screening in clinical trials resulted in only a 25 percent to 30 percent decrease in breast-cancer mortality among women between the ages of 50 and 70, and a lesser benefit was seen among women aged 40 to 49.

As significant, of all breast lesions that are biopsied following suspicious findings on a mammogram, fully 75 percent turn out, in fact, to be benign. In addition to this high rate of "false positives," current screening methods also can lead to overdiagnosis and overtreatment of some women.

Earlier identification of breast-tissue abnormalities will remain problematic, the report says, until a deeper understanding of the biology and genetics of such abnormalities makes it possible to distinguish those that are non-threatening from those that may become invasive and progress to full-blown metastatic breast cancer.

The study was sponsored by the Breast Cancer Research Foundation, the Carl J. Herzog Foundation, Mr. John K. Castle, the Jewish Healthcare Foundation, the Josiah Macy Jr. Foundation, the Kansas Health Foundation and the New York Community Trust.

Pre-publication copies of MAMMOGRAPHY AND BEYOND: DEVELOPING TECHNOLOGIES FOR THE EARLY DETECTION OF BREAST CANCER are available from the National Academy Press. The cost of the report is $45.00 (prepaid) plus shipping charges of $4.50 for the first copy and $.95 for each additional copy.

The National Research Council -- the principal operating arm of the National Academy of Sciences and National Academy of Engineering -- and Institute of Medicine are private, nonprofit institutions that provide science and health policy advice under a congressional charter.

09-Mar-2001