Film Mammography Still Best Breast Cancer Screen.
"Although many of the newer [breast cancer screening] tools offer certain advantages and deserve to be studied further, film mammography remains the gold standard for screening against which new imaging technologies must be measured," Dr. Joyce C. Lashof, an author of the report, said at a press briefing on breast cancer sponsored by the National Academies.
Clinical trials have shown that mammographic screening reduces breast cancer mortality rates by 25%-30% for women aged 50-70 and 16%-18% for women aged 40-49, according to the 227-page report.
Still, problems with the technology remain. It doesn't detect all cancers, including some that are palpable, and as many as 75% of all lesions that are seen on mammograms and biopsied turn out to be benign.
Other imaging technologies outlined in the report are already in use as adjuncts to mammography and may be especially beneficial to certain women, said Dr. Lashof, chair of the 17-member National Academies Committee on Technologies for the Early Detection of Breast Cancer, which wrote the report.
For example, ultrasound and MRI may be of value in screening women who have extremely dense breasts or have undergone a previous lumpectomy, she commented.
Digital mammography offers technical advantages, such as ease of storage and transmission of breast images, but has not been shown to be more accurate than film mammography.
Many other new technologies, such as optical imaging, positron emission tomography, and electrical impedance imaging, are at a relatively early stage of development, and more research is needed to assess their accuracy, she added.
The committee recommended more funding for research into the biology of breast cancer to find better methods of assessing the malignant potential of early-stage lesions.
These technologies could help distinguish between lesions that require treatment because of a high potential for malignancy and those that do not, such as some forms of carcinoma in situ or some very slow-growing or low-grade invasive cancers. Methods under investigation include the culturing of breast cancer cells in vitro and the identification of tumor genotypes.
The committee also recommended that the Food and Drug Administration adopt an approval process for breast cancer detection devices that is similar to its fast-tracking of drugs thought to be extremely promising.
"The FDA could approve the device [first] as a supplemental diagnostic device conditioned on the company doing studies to see whether, if used as a screening device, the technology would improve breast cancer mortality rates," said committee vice chair Dr. Craig Henderson, who is also adjunct professor of medicine at the University of California, San Francisco.