Are Breast Implants Safe for Cancer Patients?


By Diana Zuckerman, Ph.D. and Patricia B. Lieberman, Ph.D.

Although the Institute of Medicine’s report on breast implants is now very outdated, there are still plastic surgeons and other breast implant advocates that quote it.  The purpose of this article is to explain what that report did and did not include.

At the time the Institute of Medicine report was published in 1999, the major controversy about breast implants was whether it could cause connective-tissue diseases or autoimmune diseases.  There were only 17 studies on the subject at the time, but the conventional wisdom was that these studies proved that breast implants are safe.  However, a careful review of the results paints a different picture.

• These studies do not provide a comprehensive evaluation of diseases among breast implant patients. Most evaluate a few connective-tissue diseases, including such rare diseases as scleroderma and lupus. The studies would have to be much larger to determine whether implants cause these diseases. They would have to include a wider range of health information, including cancer, breast pain, need for additional surgery, and other questions, to conclusively determine if implants are safe.

• Even for the illnesses that they evaluate, the studies have limitations. In order to conduct an accurate study of implant patients’ health, patients should undergo a comprehensive medical exam. In contrast, most of these studies relied on medical records, which are likely to omit symptoms that the doctor considers less important. A few of the studies relied on self-reported illness, which were criticized because patients might exaggerate their health problems. However, the least meaningful studies were probably those that relied on hospital records; few implant patients would have been hospitalized for their symptoms, since connective-tissue disease, breast pain, and most other health problems that implant patients have reported do not require hospitalization.

• The studies included women who had implants for a short period of time, such as a few months or years. If implants cause connective-tissue diseases, it would be expected that the disease would develop over a period of years. Diseases might also be more likely after an implant breaks. Therefore, a well-designed study would include women who had implants for at least 7-10 years, not an average of 7-10 years.

• Most of the studies do not evaluate saline implants. Only one of the studies specifically evaluated the health of women with saline implants.

• Many of the studies do not evaluate the safety of implants for breast cancer patients.

Mastectomy Patients and Implants
The studies are particularly unpersuasive regarding the health of mastectomy patients. Of the cohort studies, only eight included an analysis of mastectomy patients. Four of the eight studies showed higher rates of diagnosis or symptoms of connective-tissue diseases among women with implants, but in one the difference did not reach statistical significance. The remaining studies may have been too small or may not have followed implant patients long enough to detect significant increases in disease. The case-control studies contained too few breast cancer patients to be meaningful.

Cohort Studies
Cohort studies compare women with breast implants to a group of women who are similar in terms of age, race, and health who did not have breast implants.

Edworthy et al., 1998
Does the study include mastectomy patients receiving implants? NO

Friis et al., 1997
Does the study include mastectomy patients receiving implants? YES

If so, how many? 1,435 of 2,570

Diseases studied: Any classic connective-tissue disease, including lupus, Sjogren’s syndrome, rheumatoid arthritis, and scleroderma. Also looked at “other and ill-defined” rheumatic conditions.

Were mastectomy patients analyzed separately from augmentation patients? YES

Minimum length of time with implants included in study: To be in this study a woman could have had implants for less than one year.

Average length of time with implants: 7.2 years for reconstruction group, 8.4 years for augmentation group.

Additional notes: Rates of scleroderma, lupus, and Sjogren’s syndrome in mastectomy patients receiving implants was 30% higher than expected. According to the authors, the study had only limited power to detect an increased risk of any specific connective-tissue disease. Only women who were hospitalized were categorized as ill, not outpatients.

Gabriel et al., 1994, “Mayo Clinic Study”
Does the study include mastectomy patients receiving implants? YES

If so, how many? 125 of 749

Diseases studied: Any classic connective-tissue disease, including lupus, Sjogren’s syndrome, rheumatoid arthritis, and scleroderma. Also looked at other disorders such as Hashimoto’s thyroiditis, cirrhosis, sarcoidosis, and cancer.

Were mastectomy patients analyzed separately from augmentation patients? YES

Minimum length of time with implants included in study: To be in this study a woman could have had implants for less than one year.

Average length of time with implants: 7.8 + 5.5 years

Additional notes: Women with breast implants had a 35% higher rate of arthritis, which was not statistically significant (relative risk: 1.35). Morning stiffness was 81% higher for implant patients, which was significantly higher than in women without implants (relative risk: 1.81). The authors estimated that they would need to have studied 62,000 women with implants for an average of 10 years to detect a 100% increase (or less) in rare diseases such as scleroderma.

Giltay et al., 1994:
Does the study include mastectomy patients receiving implants? YES

If so, how many? Approximately 56 of 235

Diseases studied: Rheumatic complaints, use of anti-rheumatic drugs, and medical consultations regarding rheumatic symptoms. For those reporting rheumatic symptoms, a rheumatologist made an assessment of the likelihood of a rheumatic disease.

Were mastectomy patients analyzed separately from augmentation patients? NO

Minimum length of time with implants included in study: Two years

Average length of time with implants: 6.5 years with a range of two to 14 years

Additional notes: Women with silicone breast implants reported significantly more rheumatic complaints than controls, but there was no evidence of increased prevalence of common rheumatic diseases, such as fibromyalgia, rheumatoid arthritis, or Sjogren’s disease. If mastectomy patients are more vulnerable to diseases than augmentation patients, the results may not accurately describe the health risks for mastectomy patients, since they were a small minority of the women in the study.

Hennekens et al., 1996, “Harvard Women’s Health Cohort Study”
Does the study include mastectomy patients receiving implants? YES

If so, how many? 18% of 10,830

Diseases studied: Any classic connective-tissue disease including lupus, Sjogren’s syndrome, rheumatoid arthritis, and scleroderma. Also included mixed connective-tissue disease.

Were mastectomy patients analyzed separately from augmentation patients? YES

Minimum length of time with implants included in study: To be in this study, a women could have had implants for one year.

Average length of time with implants: Not stated, but the authors analyzed the women in three groups; up to four years, five to nine years, and 10 or more years after receiving implants and showed no increased risk with increased duration of exposure.

Additional notes: Implant patients had a 25% higher rate of connective-tissue disease, whether they were reconstruction or augmentation patients (relative risk: 1.25). This was statistically significant and the researchers concluded that there is a small increased risk of connective-tissue disease among women with implants.

Nyren et al., 1998
Does the study include mastectomy patients receiving implants? YES

If so, how many? 3,942 of 7,442

Diseases studied: Hospitalizations for classic connective-tissue disease including lupus, Sjogren’s syndrome, rheumatoid arthritis, and scleroderma. Also studied hospitalizations for related diseases.

Were mastectomy patients analyzed separately from augmentation patients? YES

Minimum length of time with implants included in study: One month

Average length of time with implants: Six years for reconstruction patients, 10.3 years for augmentation patients.

Additional notes: Only women who were hospitalized for connective-tissue disease were categorized as ill, not outpatients. The authors acknowledge that the sample size was too small to draw conclusions about links between breast implants and rare diseases they studied, such as scleroderma.

Park et al., 1998
Does the study include mastectomy patients receiving implants? YES

If so, how many? 207 of 317 implanted women

Diseases studied: Signs and symptoms of connective-tissue disease, such as a antinuclear antibodies, rheumatoid factor, joint pain, fatigue, Raynaud’s syndrome, etc.

Were mastectomy patients analyzed separately from augmentation patients? YES

Minimum length of time with implants included in study: Not specified

Average length of time with implants: Six years for reconstruction patients, five years for augmentation patients.

Additional notes: Because the sample size was so small, a health risk would have to exceed 320% for reconstruction patients and 1600% for augmentation patients in order to be statistically significant. In addition, approximately half of the women had implants for less than six years. Because of these shortcomings, this study does not provide useful information.

Sanchez-Guerrero et al., 1995, “The Harvard Nurses’ Health Study”
Does the study include mastectomy patients receiving implants? YES

If so, how many? 525 of 1183 for cancer or prophylaxis

Diseases studied: Any classic connective-tissue disease, including lupus, Sjogren’s syndrome, rheumatoid arthritis, and scleroderma. Excluded women with milder or atypical cases of connective-tissue disease.

Were mastectomy patients analyzed separately from augmentation patients? NO

Minimum length of time with implants included in study: One month

Average length of time with implants: 9.9 + 6.4 years

Additional notes: According to the authors, the study does not exclude small health risks of implants that would be of public health importance. The study was designed to minimize “reporting bias” of health problems by implant patients by excluding any health problems diagnosed after May 1990, which was six months before the major media coverage of implant problems. They did not minimize bias in the opposite direction; for example, they included women who only had implants for one month. Also, they should have excluded women who reported receiving breast implants from 1952 to 1961, prior to the invention of implants. Including these women and their inaccurate statements increased the average years of implantation.

Schusterman et al., 1993
Does the study include mastectomy patients receiving implants? YES, all were mastectomy patients.

If so, how many? 250 implanted compared to 353 who had autogenous tissue transplants.

Diseases studied: Patients were considered to have rheumatic disease if they had been seen by a physician who made the diagnosis on clinical grounds with corroborating laboratory evidence and had prescribed therapy.

Minimum length of time with implants included in study: 10 months

Average length of time with implants: Less than 2.5 years

Additional notes: Length of follow up was too short to be meaningful. The authors state that the report must be considered preliminary because the onset of autoimmune disorders could occur 2-21 years after implantation.

Weisman et al., 1988
Does the study include mastectomy patients receiving implants? NO

Wells et al., 1994
Does the study include mastectomy patients receiving implants? NO

Case-Control Studies
Of the six case-control studies, only two specified that they included any women with mastectomies, and each included only one woman. Therefore, these studies are not useful for evaluating whether implants are safe for mastectomy patients.

Burns et al., 1996
Design: Case-control study of women with scleroderma.
Does the study include mastectomy patients receiving implants? YES, but only one

Englert et al., 1994
Design: Case-control study of women with scleroderma.
Does the study include mastectomy patients receiving implants? YES, but only one

Goldman et al., 1995
Design: Case-control study of women with rheumatoid arthritis and other connective-tissue disease.
Does the study include mastectomy patients receiving implants? Doesn’t specify

Hochberg et al., 1996
Design: Case-control study of women with scleroderma.
Does the study include mastectomy patients receiving implants? NO

Strom et al., 1994
Design: Case-control study of women with lupus.
Does the study include mastectomy patients receiving implants? NO

Williams et al., 1997
Design: Case-control study of women with connective-tissue disease.
Does the study include mastectomy patients receiving implants? NO