Implants May Hinder Chance for Early Detection of Breast Ca

MIAMI BEACH, Fla--Between 1 and 2 million women in the UnitedStates have received silicone-gel-filled implants for breast augmentation,and, based on the general population risk, about 10% will ultimatelydevelop breast cancer.

This translates into somewhere between 125,000 and 250,000 potentialbreast cancer cases in women with silicone implants and representsa major challenge for early detection of these cancers, MelvinSilverstein, MD, said at the 12th Annual International BreastCancer Conference.

Implants do not increase the risk of breast cancer (see storyon opposite page), but Dr. Silverstein has shown that they candelay diagnosis and thus may alter prognosis. "Patients withimplants are far more likely to be diagnosed with palpable ratherthan nonpalpable breast cancer, and to me that's a major problem,"said Dr. Silverstein, medical director of The Breast Center, VanNuys, Calif.

He stressed that patients who have been augmented "have lostaccess to state-of-the-art mammography." Screening mammographyis inadequate to detect tumors in most implant patients and hasno role in this population, he said.

Rather, such women should have diagnostic mammography, includingan examination and compression and displacement mammography inboth the mediolateral and craniocaudal views, although even theseprocedures may have a high false-negative rate, he said.

In an earlier study, Dr. Silverstein and his colleagues measuredthe amount of breast tissue that can be seen before and afteraugmentation, using both compression and displacement mammographytechniques (see figures). "Anywhere from 0 to 80% of themeasurable breast parenchyma was obscured," he said, withan 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 compressionmammography, and submuscular implants presented fewer problemsthan subglandular placement.

Size of the breast and size of the implant worked together. "Alarge breast and a small implant were better than a small breastand a large implant," he said. Whether the implant was texturedor smooth made no difference, but capsular contracture is delayedwith textured implants, giving them an edge.

In a review of 69 implant patients who subsequently developedbreast cancer, the Van Nuys researchers found that 60 (87%) presentedwith palpable disease. In 21 of 54 patients with palpable cancerwho un-derwent prebiopsy mammography, the mammogram failed toshow the lesion, for a false-negative rate of 39%, compared with8% for the typical patient with palpable disease seen at The BreastCenter.

The implant patients with palpable cancers fared no worse in termsof nodal positivity and survival than nonimplant patient withpalpable disease, but fared far worse than those who present withnonpalpable breast cancer, "and nonpalpable (occult) breastcancer is the goal," he said.

During the late 1980s, using data from his initial study, Dr.Silverstein counseled some 200 women scheduled to receive implantsabout their effects on future breast cancer screening and wasable to dissuade only two from having the operation. Nonetheless,Dr. Silverstein urged that women be apprised of the oncologicramifications of implants so that they can weigh this informationagainst the expected personal benefits of breast augmentation.