Breast Implant Answers: Understanding Silicone Gel-Filled Breast Implants

Understand the role of the FDA and the key studies of silicone gel-filled breast implants.

What is the United States Food and Drug Administration (FDA)?
What Does it Take for the FDA to Approve a Breast Implant?
Breast Implant Manufacturers' Core Clinical Studies
Core Clinical Study Conclusions
FDA's Conclusion

The United States Food and Drug Administration (FDA) is one of the United States' oldest and most respected consumer protection agencies. It has three main responsibilities:

Promoting and protecting public health by helping safe and effective products reach the market in a timely way.
Monitoring products for continued safety after they are in use.
Helping the public get accurate, science-based information about improving health.

The FDA is involved in the review of all health-related products, including pharmaceutical drugs and medical devices, to ensure they are safe and effective. In the instance of silicone gel-filled breast implants, the FDA has conducted a rigorous review process, reviewing volumes of data from several decades of research and study before confirming the safety and effectiveness of these medical devices.

In order for a breast implant to be made widely available to consumers in the United States, it must first be approved by the United States Food and Drug Administration (FDA). Usually, a two-step process is required for approval:

First, the FDA looks at data from preclinical studies of the medical device provided to them by the company seeking approval to begin a clinical study of the implant. The FDA evaluates the potential risks and benefits of the medical device and reviews the proposed clinical study. Then, as appropriate, the FDA authorizes the company to initiate and conduct the clinical study to further evaluate the safety and effectiveness of the device in humans. For breast implants, these are called Core Clinical Studies. Currently the FDA requires manufacturers to support a product approval application (otherwise known as a Pre-Market Approval application, or PMA) with a clinical study that runs for 10 years total; manufacturers may submit a PMA using data from the first two years of this study.
Second, after an appropriate amount of data are collected and analyzed by the company and submitted for the PMA, the FDA reviews all of the data and information. As part of the PMA process, the FDA convenes a panel of experts to examine the data and information provided in the PMA. These data include the results of chemical, toxicological, mechanical, and clinical testing. The panel also invites input from the public. After the FDA receives the panel's conclusions and recommendations, the FDA decides whether or not to approve the medical device, and then issues a decision.

The PMA approval process may take several years because of the time required to develop a clinical study and enroll patients, as well as to conduct other long-term toxicological testing. Also, the FDA requires companies to follow up with the enrolled patients and collect several years of data from their Core Clinical Studies so that there is reasonable assurance that questions about the safety and effectiveness of the medical device have been answered. In the case of breast implants, the FDA requires continued Core Clinical Study follow-up for 10 years to answer questions about long-term safety. Additionally, the FDA has required that breast implant manufacturers conduct large post-approval studies, such as Allergan's Breast Implant Follow-up Studies (BIFS), to further assess the devices' long-term safety.

In the early 1990s, questions arose about the long-term safety of silicone gel-filled breast implants. As a result, the United States Food and Drug Administration (FDA) asked breast implant makers to voluntarily and temporarily remove their silicone gel-filled breast implants from the market. This decision was made to allow an FDA panel to fully evaluate new safety information for these medical devices.

Shortly thereafter, the FDA allowed silicone gel-filled breast implants to remain an option for women who chose to undergo breast reconstruction surgery after a cancer diagnosis and mastectomy to restore their breast shape, as well as for women who already had breast implants, but needed to switch from saline to silicone gel-filled breast implants.

Then, as part of the FDA review and approval process, breast implant makers were required to conduct new clinical studies of their breast implant devices. These studies were designed to further evaluate the safety and effectiveness of silicone gel-filled breast implants. These "Core" studies evaluated several hundred women who underwent breast implant surgery. Researchers conducted the Core Clinical Studies in facilities nationwide with standardized protocols to ensure the accuracy, consistency and scientific integrity of the data collected. Researchers also analyzed breast implants that had been removed from women's bodies for various reasons.

The Core Clinical Study conducted by Allergan is a 10-year study designed to further evaluate and confirm the safety and effectiveness of Allergan's Natrelle™ Silicone-Filled Breast Implants in 715 women who have undergone breast augmentation, reconstruction or revision surgery. Allergan started their Core Clinical Study in 1999.

The study is looking at the effectiveness (benefit) of silicone gel-filled breast implants by measuring patient satisfaction and quality of life. To evaluate the safety of silicone gel-filled breast implants, study investigators looked for potential events such as implant rupture, capsular contracture and the need for an additional operation involving the breast implant.

Click here for a reference library of recent scientific literature and research on silicone and silicone gel-filled breast implants

Women involved in Allergan's Core Clinical Study received routine examinations after surgery (specifically at 0-4 weeks and six months post-surgery), and will continue to have annual exams for up to 10 years.

Allergan has analyzed data from the first four years of the study, which the FDA reviewed during the approval process.

What do the Core Clinical Studies show? Allergan's Core Clinical Study will continue for a total of 10 years, but the company has already provided four years of data to the United States Food and Drug Administration (FDA). The FDA reviewed these results while making their determination that silicone gel-filled breast implants are safe and should be broadly available to women in the United States.

See a full explanation of the Allergan Core Clinical Study results

Studies demonstrate that silicone gel-filled breast implants are safe, but that doesn't necessarily make them right for everybody.

Silicone gel-filled breast implants are not lifetime devices. It is possible at some point in a woman's lifetime that her implant(s) will need to be removed or replaced. To ensure that women achieve optimal results safely, patients should be aware that they should not have breast implant surgery if they:

Have existing malignant or pre-malignant cancer of the breast and have not been successfully treated
Have an active infection anywhere in the body
Are currently pregnant or nursing

You should also know that silicone gel-filled breast implants have not been clinically tested in women with*:

Autoimmune diseases like lupus or scleroderma
Conditions that could interfere with wound healing and blood clotting
A weakened immune system (such as women receiving immunosuppressive therapy)
Reduced blood supply to the breast tissue
Radiation to the breast following implantation
Clinical diagnosis of depression or other mental health disorders, including body dysmorphic disorder and eating disorders. Please discuss any history of mental health disorders with your doctor prior to surgery.

*Note that while silicone gel-filled breast implants have not been specifically tested in women with conditions outlined above, these women have not been excluded from past or current clinical tests of implants.

Researchers assessed the safety of silicone gel-filled breast implants by looking at the rate of "events", specifically, instances of implant rupture, capsular contracture and re-operation.

Read an expert’s opinion on breast surgery considerations

The results of the Allergan Core Clinical Study helped the United States Food and Drug Administration (FDA) develop information and instructions (known as "patient labeling") to help patients and consumers understand fully the potential risks and benefits of breast implant surgery with silicone gel-filled breast implants.

See more information about the Allergan Core Clinical Study

On November 17, 2006, after reviewing key data on the science, safety and effectiveness of silicone gel-filled breast implants, Dr. Daniel Schultz, Director of the United States Food and Drug Administration's Center for Devices and Radiological Health, said

"FDA has reviewed an extensive amount of data [on silicone gel-filled breast implants] from clinical trials of women studied for up to four years, as well as a wealth of other information, to determine the benefits and risks of these products."
"The extensive body of scientific evidence provides reasonable assurance of the benefits and risks of these devices. This information is available in the product labeling and will enable women and their physicians to make informed decisions."