National Academy of Sciences
National Academy of Engineering
Institute of Medicine
National Research Council
Office of News and Public Information
National Academy of Engineering
Back | Home
News from the National Academies
Date: June 21, 1999
Contacts: Cheryl Greenhouse, Media Relations Consultant
Dumi Ndlovu, Media Relations Assistant
(202) 334-2138; e-mail <news@nas.edu>

FOR IMMEDIATE RELEASE

Silicone Breast Implants Do Not Cause Chronic Disease,
But Other Complications Are of Concern

WASHINGTON -- Women with silicone breast implants are no more likely than the rest of the population to develop cancer, immunologic diseases, or neurological problems, says a new report from a committee of the Institute of Medicine. However, implants commonly lead to complications that require surgery or other medical interventions to correct.

After reviewing all relevant scientific literature on the safety of silicone breast implants, the committee determined that the most serious problems associated with their use arise when the tissue around them contracts, when the implant ruptures, or when infection occurs. As a result, many women experience substantial pain and discomfort, and many undergo surgery to replace or remove the implants.

"Although studies do not show a risk of life-threatening illness from silicone breast implants, it is clear that they can cause serious problems," said committee chair Stuart Bondurant, professor of medicine, University of North Carolina, Chapel Hill. "It is essential that women fully understand these risks before they decide to undergo this surgery."

The rate of complications varies considerably depending on the type and age of the implant, but the chance that a woman will experience a problem increases with time, the committee noted. Many women with breast implants have said that they were not provided with adequate information before receiving the implants. Researchers should monitor women for extended periods to track the incidence of health problems with implants over the long term, and health professionals should convey this information to women considering implants, the report says. Providing women with accurate information about the frequency of localized complications and further surgery is an essential part of the informed consent process.

Because many early studies on the potential health effects of silicone breast implants have been flawed, researchers have had difficulty pinpointing the health problems implants may cause. Much of the evidence examined has been anecdotal or lacked proper controls when it was analyzed, which limited its usefulness in establishing risk. However, recent epidemiological studies, as well as voluminous data on the chemicals used in implants, led the committee to several key conclusions:

> There is no evidence to suggest that the silicones used in implants are toxic to humans. When individual studies have pointed to possible toxic, immunological, or neurological effects, more extensive analyses failed to uncover associations with specific diseases or conditions.

> There is no established link between implants and a unique disease syndrome. Syndromes of the type ascribed to implants generally involve symptoms that are nonspecific and common in the general population.

> There is no evidence that conclusively links silicone to harmful effects on the immune system. Early studies addressing the immunology of silicones are limited and have substantial technical problems. Follow-up analyses have failed to uncover associations with specific immunological diseases or other conditions.

Although evidence is lacking for any relationship between breast implants and specific cancers, the presence of implants may make it more difficult to detect cancer through mammography. Special procedures must be followed by radiologists to ensure an accurate reading, the committee said. There is no evidence of increased breast cancer risk among women with implants. The report recommends that women with implants follow standard recommendations about receiving mammograms.

The committee also concluded that there is no evidence that mothers with implants pass silicone on to infants when breast-feeding. Much higher levels of silicon -- the element on which the silicone family of organic compounds is based -- have been found in cows' milk and commercially available infant formula than in the milk of nursing mothers with implants. Because of the many health benefits of breast milk to infants, the committee recommended that all mothers with implants attempt to breast-feed their infants.

Between 1.5 million and 1.8 million American women had silicone breast implants in 1997, the report says. Approximately 70 percent of these women received implants for cosmetic reasons; 30 percent received them for breast reconstruction after surgery for cancer, fibrocystic disease, or other conditions. Most modern implants consist of a rubbery silicone-based shell filled with a silicone gel or a saline solution. The report notes that in developed countries, people are commonly exposed to the kinds of materials used in implants through foods, cosmetics, lubricants for machinery, hypodermic syringes, insulators, and other products. About 10 million people in the United States have some type of implant in their bodies, such as an artificial joint or pacemaker, and many of these implants are made at least in part from silicone.

A committee roster follows. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The Institute of Medicine is a private, nonprofit organization that provides health policy advice under a congressional charter granted to the National Academy of Sciences.


Read the full text of Safety of Silicone Breast Implants for free on the Web, as well as more than 1,800 other publications from the National Academies. Printed copies are available for purchase from the National Academy Press Web site or at the mailing address in the letterhead; tel. (202) 334-3313 or 1-800-624-6242. Reporters may obtain a pre-publication copy from the Office of News and Public Information at the letterhead address (contacts listed above).


INSTITUTE OF MEDICINE
Division of Health Promotion and Disease Prevention

Committee on the Safety of Silicone Breast Implants

Stuart Bondurant, M.D.* (chair)
Professor of Medicine and Dean Emeritus
School of Medicine
University of North Carolina
Chapel Hill

Virginia L. Ernster, Ph.D. (vice chair)
Professor and Vice Chair
Department of Epidemiology and Biostatistics
School of Medicine
University of California
San Francisco

Margit L. Bleecker, M.D., Ph.D.
Director
Center for Occupational and Environmental Neurology
Baltimore

Diane V. Dado, M.D.
Associate Professor of Surgery and Pediatrics
Stritch School of Medicine
Loyola University
Maywood, Ill.

Carl J. D'Orsi, M.D.
Professor and Vice Chair
Department of Radiology
University of Massachusetts Medical Center
Worcester

Joann G. Elmore, M.D., M.P.H.
Associate Professor of Medicine, and
Adjunct Associate Professor of Epidemiology
Division of General Internal Medicine
University of Washington
Seattle

Thomas J. Fahey Jr., M.D.
Senior Vice President for Clinical Program Development
Memorial Sloan-Kettering Cancer Center
New York City

Brian E. Henderson, M.D. *
Professor of Medicine
Department of Preventive Medicine
Norris Comprehensive Cancer Center
University of Southern California
Los Angeles

Arthur C. Martellock, Ph.D.
Consultant
Pittsford, N.Y.

Chris D. Platsoucas, Ph.D.
L.H. Carnell Professor and Chair
Department of Microbiology and Immunology
Temple University School of Medicine, and
Acting Dean, College of Science and Technology
Temple University
Philadelphia

Naomi F. Rothfield, M.D.
Professor of Medicine and Chief
Division of Rheumatic Diseases
University of Connecticut School of Medicine
Farmington

Diana Taylor, R.N., Ph.D.
Associate Professor
Department of Family Health Care Nursing, and
Co-Director, Center for Collaborative Innovation in
Primary Care
University of California
San Francisco

Ralph C. Williams Jr., M.D.
Eminent Scholar and Chief Emeritus
Division of Clinical Immunology, Rheumatology, and Allergy
Department of Medicine
University of Florida School of Medicine
Gainesville

INSTITUTE STAFF

Roger Herdman, M.D.
Study Director

* Member, Institute of Medicine