Four common noninvasive diagnostic tests for breast cancer are not accurate enough to rule out breast cancer for women with abnormal findings from mammograms or physical examinations that are suggestive of breast cancer, according to a report from the U.S. Agency for Healthcare Research and Quality (AHRQ) conducted by ECRI, a nonprofit health services research agency. ECRI's evidence report found that the diagnostic tests would miss four to nine percent of breast cancer cases for women with an average risk of the disease as compared to biopsy. The report was reviewed by distinguished breast cancer researchers, including radiologists, prior to publication.

ECRI, an Evidence-based Practice Center, produced the comparative-effectiveness report for AHRQ's new Effective Health Care Program. Publicly available on AHRQ's Web site at effectivehealthcare.ahrq.gov/synthesize/reports/final.cfm, Effectiveness of Noninvasive Diagnostic Tests for Breast Abnormalities finds that each of the four tests - magnetic resonance imaging (MRI), ultrasonography, positron emission tomography (PET) scanning, and scintimammography-would miss cases of cancer if used alone to evaluate women with abnormal mammograms suggestive of breast cancer.

\"So many women today undergo biopsies only to learn they do not have breast cancer. Hopefully, noninvasive tests can continue to improve so that in the future, there will be a viable alternative to biopsy,\" said AHRQ's director, Carolyn M. Clancy, M.D. \"But early and accurate diagnosis of breast cancer is crucial, and at this time, biopsies remain the most effective technique when mammography or physical examination reveals a potential problem.\"

Mammography and physical examination are both used to detect the possibility of breast cancer. A woman with an abnormal mammogram or physical examination needs further confirmation to determine whether cancer is present. Currently, confirmation is sometimes recommended through a tissue biopsy, either by surgical excision or needle sampling. Only about one in five women currently getting a biopsy for an abnormal mammogram or breast examination has breast cancer. The need for confirmation of the mammogram means some 80 percent of women with an abnormal mammogram who undergo the biopsy procedure ultimately are found not to have cancer. Accurate noninvasive tests could reduce the number of women needing to undergo a biopsy.

A total of 81 studies met ECRI's inclusion criteria for the systematic review. Although all of the technologies evaluated could reduce the need for biopsy in women with abnormal mammogram findings who do not have cancer, each would miss some cancers. The four tests reviewed in the study, and their results, were:

-- Magnetic resonance imaging (MRI) - MRI images are created by the recording of signals generated after radio-frequency excitation of nuclear particles exposed to a strong magnetic field. For every 1,000 women with negative MRI results, about 962 would avoid an unnecessary biopsy but 38 would have missed cancers.

-- Ultrasonography - Ultrasound uses high-frequency sound waves that reflect at boundaries with different acoustic properties (e.g., between fatty breast tissue and a fluid-filled cyst). For every 1,000 women with negative ultrasound test results, about 950 women would avoid an unnecessary biopsy but 50 women would have missed cancers.

-- Positron emission tomography (PET) scanning - In PET scanning, a small amount of radioactive glucose is injected into the bloodstream. A gamma camera scanner, whole body scanner, or specific breast scanner is used for breast imaging to scan for glucose uptake. For every 1,000 women with negative PET scan results, about 924 women would avoid an unnecessary biopsy but 76 women would have missed cancers.

-- Scintimammography - Scintimammography is a nuclear medicine scan using 99mTc-sestamibi (most commonly) as a radioactive tracer injected into the bloodstream. For every 1,000 women with negative scintimammogram results, about 907 women would avoid an unnecessary biopsy but 93 women would have missed cancers.

The findings are calculated based on average risk for cancer and reflect predicted results if the technology were to be used in isolation and as a single examination following an abnormal mammogram suggestive of breast cancer. Risks for individual women may vary widely, based on factors such as age, family history, and specific findings on mammogram or physical examination. The report says that women who may wish to undergo a noninvasive procedure should discuss their individual risk of cancer with their healthcare provider.

ECRI is one of 13 Evidence-based Practice Centers carrying out effectiveness research for AHRQ's new Effective Health Care Program. In addition to performing government-funded work, ECRI delivers health technology assessment information to hospitals, health systems, health plans, and government agencies to its membership through its Health Technology Assessment Information Service? (HTAIS). HTAIS evaluates technologies along the continuum of evidence from research and development into wide utilization. The program helps organizations make informed decisions about the use of medical devices, drugs, procedures, and healthcare services.

For information about HTAIS, visit
http://www.ecri.org