Several women's health advocates are concerned about a dearth of data on the effect of silicone breast implants on different patient subgroups, including African American women and breast cancer survivors, though some plastic surgeons suggest that these worries are overblown.

"There are quite good reasons why there might be a rationale for there being differences in terms of safety outcome, complication rates, et cetera" among different ethnicities, said Susan Wood, former director of FDA's Office of Women's Health.

Wood resigned from the agency in August 2005 in protest over its handling of Barr's Plan B emergency contraceptive over-the-counter application. She joined the National Research Center for Women & Families (NRCWF) and other groups at a Feb. 2 press event to discuss a report issued by NRCWF highlighting concerns with available data for silicone implants.

At the meeting, Wood noted that different products may need to be developed for specific populations.

The NRCWF report points to the fact that African-American, Asian and Hispanic women are more likely to develop keloids, or unattractive and distortive scarring, which might lead to a higher incidence of capsular contracture, a complication caused by tight and hardened scar tissue that gives the implants a distorted appearance.

In addition, the report notes that women of color are more susceptible to autoimmune diseases. While a connection between silicone and autoimmune diseases has yet to be scientifically shown, NRCWF President Zuckerman suggested that African American women may be more susceptible to related complications.

But according to Zuckerman, there is not enough data to know for sure. No published studies have examined whether women of color react differently to breast implants than white women, she asserts. Furthermore, studies conducted by Mentor and Inamed, the two firms that have received "approvable" letters from the agency for their silicone implants, included only a very small percentage of non-white women, she claims.

However, American Society of Plastic Surgeons Vice President Roxanne Guy, MD, makes the case that the studies that have been done represent the real-world implant population. "We have some studies in the American literature that show for breast reconstruction of all types, not just breast implant reconstruction, there are not as many women of color...who have breast reconstruction," she said in an interview.

Both Guy and American Society for Aesthetic Plastic Surgery President Mark Jewell, MD, specifically fault the report's suggestions that keloid scarring has any relation to capsular contracture and that there is evidence connecting silicone implants to an increased risk of autoimmune disease.

The controversy over silicone breast implants continues to deepen as both Inamed and Mentor await final decisions from FDA; each company received an "approvable" letter last fall (¹ Also see "Mentor’s Stock Jumps In Q3 On Silicone Implant “Approvable” Letter" - Medtech Insight, 10 October, 2005., p. 14). Accusations have abounded that FDA is moving ahead without enough information and that advisory panel members who considered the issues last year may have had conflicts of interest (² Also see "Women’s Groups Urge Congress To Review Silicone Implant Panel Meeting" - Medtech Insight, 2 May, 2005., p. 15).

Data Lacking On Breast Cancer Patients, Says Wood

A substantial concern of NRCWF and others is the lack of data on the use of silicone implants in reconstruction after a mastectomy.

Since FDA took silicone breast implants off the market in 1992, they have been available only to reconstruction patients under a Compassionate Need Exemption, and patients are required to be enrolled in studies.

However, Wood suggested that the exemption has not resulted in much new data for the reconstruction population. "Sadly, those are the women who, if products come on the market, will have been least studied and need to be studied the most," she said.

"We believe that breast cancer patients differ from other women, and the impact of having a foreign body when their immune system may be compromised... could be different," Zuckerman stressed.

Although some in the medical community, including ASPS' Guy, contend that complication rates for infection are similar whether reconstruction is performed with an implant or using the patient's own tissue, Zuckerman pointed out that there is not enough data to make a conclusion.

She noted that a January 2004 FDA guidance document suggests that 25% of a study population be made up of reconstruction rather than augmentation patients, and that they be followed long term. However, she added, when Inamed decided to remove Style 153 from its PMA - the style that had been chosen by two-thirds of the reconstruction cohort - due to its high rupture rate, it was left with less than 80 breast cancer patients in the study (³ Also see "Inamed Receives Silicone Breast Implant “Approvable” Letter From FDA" - Medtech Insight, 26 September, 2005., p. 17).

Long-Term Data: Enough Is Enough, Say Surgeons

Much of the debate over silicone breast implants centers around whether there has been adequate follow-up to show long-term complication rates.

"I think it was not anticipated [by FDA] that companies would come in that quickly" after the guidance was issued, said Wood. "People thought it would require new studies, longer term studies and higher quality data resubmission, when in fact the companies came back very quickly."

In addition to urging FDA to wait until manufacturers provide 10-year follow-up data, the NRCWF is asking the National Cancer Institute and the Agency for Healthcare Research & Quality to conduct prospective and retrospective studies on silicone breast implant complications, particularly in reconstruction patients.

However, plastic surgeon Jewell stressed the adequacy of postmarket surveillance in detecting clusters of adverse events.

Moreover, Guy proffered that European studies can provide ample data to show that the implants are safe. She notes that since the U.S. ban in 1992, data has continued to present itself in the European literature on the most up-to-date devices. "The water gets muddied on this issue because many times the people that are anti-implant activists really don't differentiate the third-generation implants from the implants of the 1960s and 70s and 80s," she said.

According to Guy, the implants for which Inamed and Mentor have filed PMAs have more cohesive gel, a thicker outer shell, and a barrier layer on the shell - features which have reduced complication rates, she says.

"The naysayers are trying to create situations that call for more studies to delay the approval of these devices," Jewell charged.

"Science, I think, has spoken. We have plenty of data," he said. "I feel confident that the questions have been addressed. While no device is perfect, these are currently pretty good devices and I think have a reasonable assurance of safety, and that's good enough for me."

Groups Differ On Impact Of Silicone Breast Implants On Subgroup Populations

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