Lead authors Joseph K. McLaughlin, Ph.D., and Loren Lipworth, Sc.D., of the International Epidemiology Institute, Rockville, Md, and the Vanderbilt University Medical Center, Nashville, Tenn, performed the review to evaluate the risk of cancer after cosmetic breast implants.
The results have been "remarkably consistent" in showing no evidence of an increase in breast cancer or other cancers among women with breast implants.
One study reported an increased risk of lung cancer, but that was explained by the much higher rate of smoking among women with implants.
Another concern has been that implants would interfere with the detection of early-stage breast cancers by mammography. Some studies suggest that mammography may in fact be less sensitive in women with implants.
However, no study to date has found evidence that breast cancer survival rates are lower in women with breast implants.
The research team said that numerous studies have "unanimously concluded" that there is no relationship between breast implants and connective tissue diseases (CTDs) such as fibromyalgia, systemic lupus erythematosus, or rheumatoid arthritis. These are the disorders that were anecdotally reported and began the implant health scares in the early 1990s.
The review also finds "no credible evidence" that implants are linked to some "atypical" or "mixed" type of CTD, or to neurological diseases such as multiple sclerosis. There is also no evidence that children born to women with breast implants are at increased risk of birth defects or other health problems.
Only one association has been consistently reported in women with breast implants: suicide. This includes a recent study by the International Epidemiology Institute group showing a threefold increase in long-term suicide rate among women with cosmetic breast implants.
The increase in suicide—together with increased rates of death from alcohol or drug dependence—is unlikely to be directly related to breast implants per se. Rather, the associations highlight the importance of mental health screening and follow-up for women seeking breast implants.
In contrast to the extensive data on health outcomes such as cancer and CTDs, relatively few studies have evaluated the risks of implant rupture/leakage of the silicone gel.
The highest-quality incidence study of the issue suggests that 98 percent of implants are intact five years after surgery, and 85 percent at ten years. In most cases, rupture is a relatively harmless condition that does not cause any significant health problems.
Other studies have suggested that local complications of breast implants, such as infections and pain, are uncommon and usually do not require further surgery. Contractures—hardening of the tissues around the implant—are the most frequent reason for additional surgery.
"We conclude that the weight of the epidemiologic evidence does not support a causal association between breast implants and breast or any other type of cancer, definite or atypical CTD, adverse offspring effects, or neurologic disease," Dr. McLaughlin and colleagues said.
The research team has called for further studies to evaluate the well-documented increase in suicide rates after cosmetic breast implant surgery—including whether psychiatric illness is already present before breast augmentation surgery or if it develops afterward.
The new study is published in the November Annals of Plastic Surgery.