MIAMI BEACH, Fla--Between 1 and 2 million women in the United States have received silicone-gel-filled implants for breast augmentation, and, based on the general population risk, about 10% will ultimately develop breast cancer.
This translates into somewhere between 125,000 and 250,000 potential breast cancer cases in women with silicone implants and represents a major challenge for early detection of these cancers, Melvin Silverstein, MD, said at the 12th Annual International Breast Cancer Conference.
Implants do not increase the risk of breast cancer (see story on opposite page), but Dr. Silverstein has shown that they can delay diagnosis and thus may alter prognosis. "Patients with implants are far more likely to be diagnosed with palpable rather than nonpalpable breast cancer, and to me that's a major problem," said Dr. Silverstein, medical director of The Breast Center, Van Nuys, Calif.
He stressed that patients who have been augmented "have lost access to state-of-the-art mammography." Screening mammography is inadequate to detect tumors in most implant patients and has no role in this population, he said.
Rather, such women should have diagnostic mammography, including an examination and compression and displacement mammography in both the mediolateral and craniocaudal views, although even these procedures may have a high false-negative rate, he said.
In an earlier study, Dr. Silverstein and his colleagues measured the amount of breast tissue that can be seen before and after augmentation, using both compression and displacement mammography techniques (see figures). "Anywhere from 0 to 80% of the measurable breast parenchyma was obscured," he said, with an average loss per film of 28% of the measurable surface area.
Severe capsular contracture caused the most loss of visualization. Displacement mammography provided better visualization than compression mammography, and submuscular implants presented fewer problems than subglandular placement.