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Silicone gel-filled breast implants first became available in the United States in 1962. In the early 1980s, anecdotal reports introduced concern among public advocates and regulatory agencies that there was not enough evidence to support the safety of these implants. These groups raised questions related to several diseases and conditions, including whether women with silicone gel-filled breast implants experience an increased risk of breast cancer or other cancers, and whether implants make it less likely that a woman or her doctor would detect breast cancer early, when it is generally more treatable and curable.

Since that time, a number of independent review panels have evaluated the scientific evidence to determine whether there is an association between silicone gel-filled breast implants and serious health issues, such as various types of cancer. Between 1999 and 2005, the Institute of Medicine (IOM), the National Institutes of Health (NIH), the International Agency for Research on Cancer (IARC), and the European Committee on Quality Assurance and Medical Devices in Plastic Surgery (EQUAM) all published reports concluding that women with silicone gel-filled breast implants do not experience increases in breast cancer, as compared to women without breast implants in the general population, and there is no causal association to cancer of any type.1,2,3,4

Understanding the Studies on this Topic

Epidemiologic studies look at the frequency and distribution of a specific health condition among a large number of people over a long period of time, to develop scientific conclusions about what is causing that condition. They are among the best methods we have to determine "cause and effect" related to specific health conditions. It is important to note that, while these studies can be exceptionally helpful, their results can be misleading if the study is not designed carefully. When looking at the rate of a specific disease among women with silicone gel-filled breast implants and those without, it is crucial that researchers select "like" women for study and control groups, who are in the same general age group and lead similar lifestyles. This is critical, because factors such as age, diet, exercise, smoking habits, etc. can increase or decrease the occurrence of certain conditions, including cancer.

None of the epidemiologic studies that evaluated breast cancer have found a link between saline-filled or silicone gel-filled breast implants and the occurrence of breast cancer in particular.

A large study conducted by the National Cancer Institute (NCI) included 13,488 women who had breast implantation surgery for aesthetic reasons and compared them with 3,936 women of similar age who had other types of plastic surgery, as well as with women in the general population. The study followed these women for more than 11 years, in order to determine the long-term health risks, and found no difference between the two plastic surgery groups in the risk for breast cancer overall.

With respect to other specific types of cancer, the NCI study mentioned above reported slightly increased risks for lung, cervical and vulvar cancer and leukemia among women with breast implants, as compared to women in the general population. These higher risks are unlikely to be related to silicone exposure, but instead may be due to chance, the way in which participants were selected for the study, or lifestyle or reproductive factors common to women who choose to have implants.5 This was the only study to date that initially reported a statistically significant increased risk of death from brain cancer among women with breast implants; however, these findings are complicated by the fact that cancer in the brain often comes from cancer that starts at other sites in the body. In addition, and importantly, the most recent report from this study (which is based on an average of 20 years follow-up after breast implantation), demonstrated there was no longer a statistically significant increased risk for brain cancer.6

In addition, numerous epidemiologic studies conducted in North America and Europe have addressed questions related to the risk of cancer among women with silicone gel-filled breast implants. One of the largest epidemiologic studies investigating the long-term health effects of silicone gel-filled breast implants was conducted in Canada among 24,558 women with breast implants, compared with the general population of similar-aged women and with women who had undergone other types of plastic surgery. The occurrence of cancer overall was not higher among women with implants than among women in the comparison groups.7

Two of the most recent epidemiologic studies exploring this issue, based on 2,736 Danish women followed for more than 14 years (with a range of up to 30)8 and 3,486 Swedish women followed for more than 18 years (range up to almost 39)9, also found no statistically significant increase in the overall incidence of cancer among women with silicone gel-filled breast implants, as compared to women of similar age who did not have breast implants. In a study of 2,171 Finnish women with silicone gel-filled breast implants followed for an average of just over 8 years, cancer incidence overall was also similar to that in the general population.10

While the epidemiologic study of 3,486 Swedish women noted above found no increase in overall cancer incidence, it did find a significant increase in lung cancer among women with breast implants.9 However, an earlier survey based on a randomly selected group of women from this study found that they were 2.8 times more likely to be current smokers than the general population.11

In addition to the studies that have investigated whether silicone gel-filled breast implants are related to the development of breast or other cancers, there have been numerous studies exploring the question of whether breast implants result in delayed breast cancer diagnosis due to interference with mammography. Several epidemiologic studies have concluded that, while the sensitivity of mammography may be reduced to some degree in women with breast implants, this does not result in delayed diagnosis of breast cancer or lower rates of survival among women with breast implants who are diagnosed with breast cancer.8,9,12,13,14,15

In summary, it is clear that medical professionals and the scientific community have taken very seriously any potential for an association between silicone gel-filled breast implants and cancer, and have conducted many thorough, comprehensive studies to determine whether or not there is a relationship. Based on the results of these investigations and studies, there is no credible evidence of a causal association between silicone gel-filled breast implants and any type of cancer. In addition, some investigators have reported a decreased incidence of breast cancer in women with breast implants, as compared to those without.9 This finding warrants further research. It could be a result of chance or could be due to the fact that women with breast implants are generally attuned to their health (in other words, differences in lifestyle) or that they tend to have more routine breast cancer screenings.

Q.

But what about other types of cancer?

A.

As noted above, results from numerous large, well-controlled epidemiologic studies that evaluated this question consistently indicate that there is no causal association between silicone gel-filled breast implants and any type of cancer.

Q.

Is it safe for women with breast implants to have a mammogram? And when they do, is it effective?

A.

Yes, it is safe for women with breast implants to have mammograms. If you have breast implants, do not alter the mammogram screening schedule you have agreed on with your physician – the risks of not detecting a cancer because you avoid a screening far exceed any risk of damage to the breast implant. Ask your physician to direct you to a screening facility that practices implant displacement technique, which has been shown to improve the accuracy of mammograms in women with breast implants.

Q.

Where can I find more information on silicone gel-filled breast implants and cancer?

A.

The National Cancer Institute (NCI) is a very good source of information on this topic.

• Click here for the NCI's Breast Implant Study Fact Sheet
• Click here for a report about breast implants from National Institutes of Health (NIH)
• Click here to view a comprehensive list of related studies

1 Bondurant S, Ernster V, Herdman R. "Safety of Silicone Breast Implants, Report of the Committee on the Safety of Silicone Breast Implants, Institute of Medicine." Washington, D.C.: National Academy Press, 1999.
2 National Institutes of Health. "Breast implants: status of research at the National Institutes of Health." Amended report 3/24/2005. http://orwh.od.nih.gov/pubs/rev305breastimplantsreport.pdf
3 International Agency for Research on Cancer. "Surgical implants and other foreign bodies." IARC Monograph on the Evaluation of Carcinogenic Risks to Humans, Volume 74. Lyon: IARC Press, 1999
4 European Committee on Quality Assurance and Medical Devices in Plastic Surgery. "Consensus declaration on breast implants, 23-6-2000." Israel, European Committee on Quality Assurance (EQUAM). 4th Consensus Declaration.
5 http://www.cancer.gov/newscenter/siliconefact sheet
6 Brinton, LA, et al. "Mortality rates among augmentation mammoplasty patients: an update." Epidemiology 2006;17(2):162-169.
7 Brisson, J., et al. "Cancer incidence in a cohort of Ontario and Quebec women having bilateral breast augmentation." Int J Cancer 2006;118(1):2854-2862
8 Friis S., et al. "Cancer risk among Danish women with cosmetic breast implants." Int J Cancer 2006;118(4):998-1003.
9 McLaughlin, JK, et al. "Long-term cancer risk among Swedish women with cosmetic breast implants: an update of a nationwide study." J Natl Cancer Inst 2006;98(8):557-560.
10 Pukkala, et al. "Incidence of breast and other cancers among Finnish women with cosmetic breast implants, 1970-1999." J Long Term Eff Med Implants 2002;12(4):271-279.
11 Fryzek, JP, et al. "Characteristics of women with cosmetic breast augmentation surgery compared with breast reduction surgery patients and women in the general population of Sweden." Ann Plast Surg 2000;45(4):349-356.
12 Deapen, D, et al. "Breast cancer stage at diagnosis and survival among patients with prior breast implants." Plast Reconstr Surg 2000; 105(2):535-540
13 Hoshaw, SJ, et al. "Breast implants and cancer: causation, delayed detection and survival." Plast Reconst Surg 2001;107(6):1393-1407
14 Miglioretti DL, et al. "Effect of breast augmentation on the accuracy of mammography and cancer characteristics." JAMA 2004;291(4):442-450
15 Holmich, LR, et al. "Stage of breast cancer at diagnosis among women with cosmetic breast implants." Br J Cancer 2003;88(6):832-838