Breast implants: Do they affect mammograms?
Breast augmentation surgery is the second most popular plastic surgery performed today — 500,000 American women are expected to undergo the procedure in 2006 alone. If you're considering having breast implants or are one of the many women with them, there are a few things you should know when it comes to screening for breast cancer. Dr. Judith Reichman, a show contributor and gynecologist, was invited on “Today” to share the latest information.
It’s estimated that 4 million women have undergone breast implant surgery in the U.S., and that 500,000 more will do so in 2006. How do these implants affect breast cancer screening? Do implants put a woman at greater risk for breast cancer or cause a risk of late detection because they “hide” early cancers? Are mammograms less effective in women with implants; can they cause them to rupture?
Do breast implants, especially silicone ones, cause medical problems?
Breast implants were first introduced in 1962. Since then, over 250 types have been created. In general, they all have an external shell that contains silicone and a filler material, which consists of saline (salt water), silicone gel, or oil. In the 1980s allegations were made that silicone gel implants could be linked to cancer, autoimmune disorders (such as lupus), and other systemic diseases. Numerous lawsuits were filed and millions of dollars were paid out to women (and their lawyers) to settle these complaints. The U.S. Food and Drug Administration requested safety data on the implants but after 30 months, when it didn’t get what it deemed to be “enough,” the federal agency briefly banned the general use of gel breast implants for augmentation, with the exception of women who required breast reconstruction subsequent to breast cancer and mastectomy. The FDA revised this ban in 1993 and allowed gel breast implants to be used in controlled clinical studies.
Most experts now feel that there is insufficient evidence on which to base conclusions that silicone implants are the cause of health problems related to the immune system and systemic tissue disorders. Silicone implants have been widely used in Europe and Asia. Many women and surgeons feel that this type of implant looks better and feels more natural than one filled with saline. In 2005 an FDA advisory panel did recommend that one manufacturer’s (Mentor) silicone implants be approved if:
- Patients sign a specific consent.
- The implants are used by board certified surgeons.
- The patients are tracked for tolerance and rupture.
- Patients get an MRI scan five years after insertion, and repeat it every two years.
More and more women have opted for breast augmentation as the much publicized trials and tribulations about implants have faded from media attention and a qualified soon–to-come FDA clearance of some types of silicone implants seems imminent.
Does an implant obscure early breast cancer detection through mammogram?
The implants do diminish full breast visualization during mammography. The most important factor is where the implants are placed. Those “inserted” below the chest muscle are less likely to obscure a mammographic view than those placed above. Both silicone and gel implants are to some degree radio opaque (they look like white “blobs” and may prevent visualization of the tissue below). Depending on which studies are cited, it’s estimated that implants obscure between 15 percent to more than 50 percent of breast tissue.
In addition to the whitening out of tissue below it, an implant can affect the rest of the architecture of the breast tissue by displacing and compressing it so that the hallmarks of early breast cancer — micro calcifications, tissue distortion and small dense masses — are not seen. Because implants are less compliant then breast tissue they also limit the amount of compression needed for optimal breast visualization during mammography. And finally, calcifications due to scarring around the implant may mimic cancer.
So, is it still worthwhile to get a mammogram?
Absolutely, yes. Don’t forget that more than 75 percent of women with breast cancer have no risk factors for this disease. And universal screening has been shown to decrease mortality from breast cancer by 33 percent in appropriately screened women. Having given some pessimistic views on the “viewing” of augmented breasts, it should be noted that with experience, mammographers now know how to get a better image of a breast containing an implant. If the implants are placed under the chest muscle (the pectorals), they won’t cover or hide as great an area of breast tissue. (About 50 percent of implants are placed under the muscle, the rest are under the breast tissue but above muscle.) In all cases, instead of the two standard views taken for each breast, four views should be done. And if possible, in one of the views the implant should be pushed back against the chest wall allowing the breast tissue to be pulled forward while imaged. This technique may improve evaluation in as much as 92 percent of patients.
Will the pressure of a mammogram cause an implant to rupture?
There were only 41 cases of implant ruptures during mammography reported to the FDA between June 1992 and October 2002. Another 17 cases related to mammograms have been reported in the medical literature. This occurrence is obviously quite rare. So, implants should not be a disincentive to getting a mammogram. Some of my patients ask if ultrasound, which is a gentler procedure, can be used to screen for cancer in lieu of mammogram. My answer is no. Ultrasound doesn’t pick up the minute calcifications of early breast cancer. And it is very operator dependent; results vary tremendously based on who is performing and viewing the image. Ultrasound is an adjunct test used to distinguish between solid and cystic masses or to help assess very dense breasts. The current practice is not to use it as a primary screening tool to detect breast cancer in women without or with breast implants.
What about MRI?
This can be used to detect a silent rupture in a silicone implant. But routine use for breast cancer detection is still limited to high-risk women (those who have a strong genetic history, are known to have BRCA mutations or who have had previously diagnosed breast cancer). The MRI may indeed become the test of the future. But currently it’s very expensive and has a high rate of false positive results (findings that require a biopsy but turn out to be benign).
Do women with implants experience higher incidences of breast cancer?
No. Many studies have found that breast cancer incidence in women who have had implants is actually lower than that of the general female public. One study from Sweden followed 3,400 women who had received cosmetic breast implants between the years 1965 and 1993. They had an average follow-up of 18 years. The women with implants were found to have a 30 percent reduced risk for breast cancer when compared to women without implants. Another study, this time in the U.S., compared breast cancer incidence rates among 13,000 women who had breast implants with expected rates based on U.S. surveillance. And here too the risk was slightly lower. It’s possible, though many feel not medically probable (or even statistically proven) that breast implants may decrease breast cancer incidence by:
- Compressing breast tissue and interfering with its blood supply.
- Decreasing temperature in the breast.
- Stimulating an immunological response, which helps destroy potential breast cancer cells.
It may be, however, that the apparent decreased incidence of breast cancer in women with breast implants reflects the fact that these women are more likely to be thin (obesity is a significant risk factor for breast cancer). Also, the women with implants tend to be in a higher socioeconomic group with better nutrition, exercise, and cancer screening. They see their physicians, especially the breast specialist more frequently, have more frequent mammograms and better access to medical care than their cohorts who don’t have implants.
When cancer is found in women with implants, is the disease at a later stage?
This has been addressed in another study published in The Journal of the American Medical Association (JAMA), which used the data collected from the National Cancer Institute funded Breast Cancer Surveillance Consortium (BCSC). They compared 141 women with augmentation and nearly 21,000 without who were diagnosed with breast cancer between 1995 and 2002. The tumors were diagnosed at a similar stage and size, but tended to be lower grade (less worrisome) for women with breast augmentation compared to those without. The authors concluded that “although sensitivity of screening mammography is lower with breast augmentation, there’s no evidence that this results in more advanced disease at diagnosis compared with women without augmentation.”
What happens if a mammogram demonstrates a suspicious area?
In some cases, an open biopsy (with an incision into the breast) rather than an ultrasound guided needle biopsy or stereotactic biopsy may be required so that the implant is not punctured. But with the right expertise this is not necessarily the case. There is no question that the expertise of the physician who evaluates an abnormal finding by performing a biopsy (either the radiologist or breast surgeon) can determine the type of procedure that will be performed. And if cancer is found, the implants, especially if placed above the chest muscles, may make it less amenable to treatment with “just” lumpectomy and radiation. It can be difficult to achieve a cancer-free surgical margin while preserving the implant. Radiation may also cause the implant to harden and contract.
Dr. Reichman’s Bottom Line: Breast implants do not increase your risk of breast cancer. Don’t raise your risk of a delayed diagnosis by letting your implants prevent you from getting a mammogram.
Dr. Judith Reichman, the “Today” show's medical contributor on women's health, has practiced obstetrics and gynecology for more than 20 years. You will find many answers to your questions in her latest book, "Slow Your Clock Down: The Complete Guide to a Healthy, Younger You," which is now available in paperback. It is published by William Morrow, a division of HarperCollins.