Breast implants are made from silicone rubber envelopes that contain either saline (salt water), or a silicone gel, (made up of silicone molecules of lower molecular weight than the rubber shell).
Among the myths propagated about silicone has been that it is a largely untested substance used in an "experimental" way on unsuspecting patients. In fact, it was chosen as the basis for breast implants in 1960-62 because of its many-year history of successful performance in other implantable devices. Substantial laboratory and clinical evidence already existed at that time to show that the material was very well tolerated in most circumstances. Silicone was then, (and is now), the standard by which the inertness of other polymeric biomaterials is judged.
Do Silicone Implants Cause Cancer?
The original interest in breast implants and their possible relationship to cancer was based upon the rediscovery of old, poorly understood laboratory findings from the 1940's and 50's. Nearly a quarter of lab rats will develop the rare cancer, fibroscarcoma at the site of silicone implantation. However, this reaction (the so-called Oppenheimer effect) is not limited to silicone, but will follow the implantation of any smooth surface, including that of other plastics or of glass. This reaction is peculiar to rats, and has never been observed in humans. Large studies were carried out in Los Angeles and in Canada to look at the incidence of standard breast cancer in women with implants. Both of these studies clearly showed that there is no increase in breast cancer among women with implants.
Do Implants Cause Immune-related Disease?
Concerns about a possible relationship between breast augmentation and auto-immune disease date back to the 1960's in Japan. Dr. Myoshi described two women (prostitutes) who developed polyarthritis many years after undergoing breast enlargement by illicit paraffin injections of the breast. He wondered if the wax had served as an "adjuvant," or agent acting to heighten a predictable immune response.
Western literature review of this and other cases from Japan did not occur until 1984. After this, anecdotes appeared describing women who complained of various chronic, non-specific symptoms ( e. g. fatigue, muscle and joint pain) at varying times after breast augmentation with implants. These reports in no way established a causal relationship between the women's symptoms and their previous breast surgery, and early epidemiologic studies of this question failed to show any difference between women with prostheses and those without. However, the notoriety of this issue and the growth of litigation made the FDA step in and ban the use of gel implants beginning in 1992.
Some studies reported since then suggested that some silicones may act as adjuvants, heightening normal immune reactions to other things. There were not any works, however, which showed silicone itself to generate a specific antibody response, however. Other research suggested that combinations of silicone and protein might lead to antibody generation, but these antibodies could also be found in people who had no implanted devices. Also, the mere presence of antibodies in no way indicates a disease state. Large epidemiological studies performed at the Mayo Clinic and Harvard then provided strong evidence that breast implants are not related to auto-immune disease or rheumatologic symptoms. As a result, the American College of Rheumatology recommended to FDA that gel implants be returned to the market. Notwithstanding this fact, only saline implants were generally available for primary breast augmentation surgery in the United States until recently, (European and South American physicians and hospitals continued to use gel devices during the American ban). Some years after the National Institutes for Health published its famous white paper indicating a lack of causality between silicone use and illness, the FDA revisited the issue. As a result of the 2007 re-evaluation of "Pre-Market Approval" data from implant manufacturers, FDA acted to return silicone gel breast implants to the general market.
Do The Devices Hide Disease?
We now know that early detection of breast cancer can have an impact upon patient survival. Because nearly 1 in 9 American women will develop breast cancer, surgical changes in the breast which might make tumor surveillance more difficult should be carefully considered. Since breast implants do not transmit xrays well, they can render standard screening mammography less effective. Also, tissues which are compressed by implants appear more dense and difficult to read on xray. Finally, the fine calcifications which occur in some women around breast implants may at first confuse the diagnostic picture.
With all these concerns acknowledged, we must still be careful not to unsupportedly conclude that cancer diagnosis is delayed in women with implants. There are, in fact, conflicting data on this issue. Clearly, women considering breast augmentation must be made aware of the need for special follow-up and imaging studies in the future, and should be motivated to be even more fastidious about breast health than others. Those with strong family history of breast cancer should pursue breast augmentation only after an exhaustive consideration of these issues. Studies now show, however, that with proper examination and radiographic techniques, radiologists experienced in the imaging of the implanted breast can find tumors as small as those found in women without prostheses. Women should seek counsel from their plastic or general cancer surgeon regarding referral to a breast imaging center with the proper expertise. Mammography in these centers will always involve additional views and will usually employ special maneuvers to draw the breast off the implant. Ultrasound or scan can also be used in those situations where standard techniques are insufficient.
Advice on Silicone Devices
During the last decade and a half, concerns were raised in the media and within the Food and Drug Administration regarding the safety of silicone breast implants. The legitimate concerns of women regarding this issue was in some instances raised to the level of frenzy by virtue of "talk show" debate having supplanted the scientific process. That breast implant surgery has both side effects and potential complications is undeniable. However, statements from self-professed experts implied that a host of frightening and serious complications were commonplace among implant patients.
Dr. Philip Godfrey is a New York plastic surgeon specializing in plastic surgery of the breast and trunk. After having treated and advised a large number of women with implant related problems and concerns he reports that "...if women's interests are truly to be served, frank and accurate consideration of all relevant issues must take place; first, between each patient and her doctor, and second, within the public arena into which so much unwarranted fear has been introduced. "
Dr. Godfrey describes the worries as falling into four main areas:
- Hardening of implants.
- The question of implant longevity and the risks of inflammatory side effects from free silicone gel.
- The conjectural relationship between breast implants and cancer.
- The conjectural relationship between silicone and systemic rheumatologic illness.
"Hardening"of Implants
Although implants themselves do not become hard, the breast augmented or reconstructed with an implant will occasionally become firm. This firming, (which in some women is severe enough to produce true hardness and even pain), results from a normal physiological response to surgery. "All wounds, whether containing foreign objects or not, heal in part through a mechanism known as 'contraction,'" says Dr. Godfrey. While in many instances contraction produces nothing of a discernibly deleterious nature in the patient, there are circumstances in which it may lead to unwanted consequences. "A common example is seen in the instance of a healing, open wound found near a joint. If the scar generated in healing tightens sufficiently to limit joint motion, a 'contracture' is said to exist. Surgical intervention is in many instances required to deal with such problems to restore normal movement."
Persistent, active contraction of the wound around a breast implant may lead to analogous problems for a patient. As the spongy, gel device is confined to smaller and smaller volumes, it becomes less compressible and more spherical in shape. When these changes are mild (as in many cases), they may not even be clinically evident. For some, however, contraction continues to the point of producing disappointing firmness and shape change in the breast. This is described as "capsular contracture".
Dr. Godfrey reports, "...our understanding of contracture remains incomplete, and we are unable to predict for an individual patient the degree to which she might suffer from hardening. Also, because of variability in measurement techniques and in patient follow-up, it has been difficult for plastic surgeons to generate a broad, extended database on contracture which they could share with patients pre-operatively." (Most patients with good results follow-up with their doctors only sporadically, while virtually all patients treasure the confidentiality that inclusion in large studies seems to threaten). Consequently, "...surgeons must describe the risk of contracture to their patients based upon their own experiences or upon published studies regarding relatively small populations of patients."
The symptomatic contracture rate has clearly declined over the years, a likely result of refinement in both implants and surgical technique. Placement of implants beneath chest muscles rather than just beneath the breast seemed in the past to lower the contracture rates. However, the individual aesthetic and functional priorities of the patient must be considered in decision-making about implant position, and many today believe that modern implants fair as well above the muscle as below. Some data suggest that saline (salt water) filled implants may illicit contracture slightly less often than do silicone gel devices, and research continues to determine if "texturing" (roughening) of the implant's outer surface may also mitigate contracture. The implant technology acknowledged as most helpful in the prevention of contracture is no longer available (polyurethane), having been removed from the market when its "Pre-Market Approval Application" was denied by the FDA. (See under "Implants and Cancer" below).
Once significant contracture occurs, several options are open to the patient according to Dr. Godfrey. She may, of course, choose to accept contracture that is not severe, (many do this). Reliable, if sometimes temporary, relief of contracture is obtainable through surgery to cut the scar surrounding the prosthesis, ("open capsulotomy"). If the implants are removed, contracture will cease. Those patients unwilling to be without prostheses, however, will need to accept the risk of re-contracture after insertion of new implants. Studies have shown that re-contracture is less likely if implant replacement is preceded by complete surgical removal of the old scar capsule, ("capsulectomy'). This latter maneuver does make the surgery more formidable and engenders certain risks which implantation or explantation alone does not involve.
The capsule of scar can sometimes be disrupted and thereby released by manual compression of the breast by the doctor, ( so-called "closed capsulotomy"), avoiding the need for an operation. Dr. Godfrey counsels against this treatment, stating that the high rate of re-contracture and the risk for implant rupture that attend this procedure have led most surgeons to abandon its practice.
Implant Longevity
Ideally, implantable devices would have indefinite life spans within the body. However, breast implants, like joint replacements, heart valves, and myriad other useful items, have limited longevity. "It is the common experience of plastic surgeons that most gel implants last for many years, but we are unable to present patients with numbers from large series which prove this to be so," says Dr. Godfrey. Manufacturers' data suggest an overall "failure" rate of < 1 % in the first 2 years, but longer term data are still being developed. Also, because implant technology has changed in many ways over the last 30 years, it is difficult to generalize in one's conclusions based upon the performance of any particular implant type. More research is needed.
Because implant failure necessitates re-operation, it is a topic of legitimate interest to patients and surgeons alike. A corollary concern centers upon the biological consequences of extruded implant contents laying within the body's tissues. For saline implants, little apprehension seems justified because of the unquestioned bio-compatibility of salt water. However, despite a substantial body of experimental evidence suggesting the relative bio-inertness of silicone, free gel must certainly be viewed more skeptically.
It has always been the intent of manufacturers and surgeons that silicone gel remain contained within the elastomer shell of the prosthesis. Components of gel will not infrequently illicit dramatic inflammatory reactions in tissue and may damage cutaneous or breast architecture in a manner which is only remediable with surgical resection. Such reactions have most often been seen after illegal injections of adulterated silicone directly into the breast. However, if gel escapes the confines of the capsule (as in simultaneous implant and capsule rupture), inflammatory lesions of a like nature can be encountered. Most plastic surgeons agree that once diagnosed, gel implant rupture demands timely explantation. Also, Dr. Godfrey feels that capsulectomy (removal of the scar capsule) is justified in these cases, as it offers the best chance for complete removal of gross foreign matter. Happily, modern, "cohesive" gel implants seem to liberate very little gel into surrounding tissues even when the shell of the device is breached.
Saline implants appear to leak more frequently than silicone gel implants, sometimes from "fold flaws," (areas of wear fracture at edges) or from leaking valves. While there is no medical consequence form saline leakage, the patient will need re-operation for removal or replacement of the implant(s). Implants often last decades, but may sometimes fail within a few years.
Implants and Cancer
All medications and bio-materials are tested for their cancer-producing potential. Studies on silicone over a period of more than four decades reveal no "carcinogenic" (cancer-producing) activity. On more than one occasion, and as recently as 1987, however, this conclusion has been called into question by the report of cancers growing in rats at the site of silicone implantation. These rare tumors, (called "fibrosarcoma") develop in about one quarter of all rats with smooth, subcutaneous implants. Silicone, polyethylene, and even glass will produce tumors if the implant's surface is smooth. Experts agree that this so-called "Oppenheimer effect" is related to the physical nature of the implant (rather than its chemical composition), and is only seen in rats. No humans have been found with cancers in association with breast implants.
Years ago , implants covered with polyurethane foam were sometimes used because of their superior record in preventing capsular contracture. Evidence of the slow, partial degradation of the foam after implantation prompted questions regarding the ultimate fate of the material and the effect of its breakdown products upon the body. Evaluations by the scientific community and by FDA suggested an extremely small cancer risk from this breakdown, but the product was withdrawn from the market by a manufacturer uninterested in the expensive and time-consuming retesting which would be necessary for new approval from FDA. Dr. Godfrey states that "it is still the recommendation of the FDA that women not seek implant removal for reasons of cancer fear, but only if local, implant-related problems become evident."
Any fear of a causal relationship between implants and breast cancer can be safely allayed on the basis of both American and Canadian epidemiological studies. These large investigations show in a convincing way that risk for breast cancer is not increased by the presence of implants. Less certain is what role implants might play in delaying the diagnosis of breast cancers, given the fact that all these devices transmit xrays poorly and thereby hinder mammography. Notwithstanding this fact, evidence is mounting that implant patients who are appropriately followed with regular exams and special mammography are diagnosed no later than women without implants. "It is critical that all women considering breast implant surgery be advised of the need for special cancer screening efforts post-operatively," according to Dr. Godfrey.
Silicone and Rheumatalogic Illnesses
During the 1960's, Japanese doctors observed what they believed might be an extraordinary incidence of rare rheumatologic illness (scleroderma) among prostitutes with breast augmentation. These women had undergone direct injection of the breasts with paraffin (wax) and presented years later with rheumatologic complaints. After 1984, sporadic reports appeared in western scientific journals describing rheumatologic disease in women with breast implants. Although these reports in no way established a causal relationship between silicone implants and the so-called "auto-immune" rheumatic disorders, they did make clear the need for more specific investigation. Data available today do not support a link between silicone implants and the more common of these illnesses (e.g. rheumatoid arthritis), and the newest, most powerful studies also indicate that the rarer illnesses are also unrelated to silicone. It has been the position of the American College of Rheumatology for some time that no link between breast implants and these maladies exists. Review of all available data relating to this issue has led the National Institutes for Health to proclaim that no relationship appears to exist between breast implants and rheumatologic disease or symptom complexes.
Dr. Godfrey has seen a large number of women with such complaints, and works to help them understand what science is saying on this issue. "Women with joint or muscle complaints and no evidence of local inflammatory problems within the implanted breast must be discouraged from considering explantation a treatment of their symptoms. Even though every woman has the right to remove her implants if she so chooses, we have to report that our explantation experience has thus far produced gratifying results only in women with physical evidence of 'local,' implant troubles."
Summary
Many questions have been raised regarding the safety of breast implants. Most concerns have already been well addressed by science, while others require further research. This continuing exploration for answers is in no way unique to breast implants, but characterizes the methods used in the ongoing evaluation of all procedures and materials.
Local problems related to the medical use of foreign materials can and do occur. However, patients with breast implants in whom such problems cannot be identified are best advised not to seek surgery. Unfortunately, Dr. Godfrey relates that "...we have already begun to see significant complications attending some surgery performed for 'implant anxiety' alone."
