IMPORTANT INFORMATION: Dr. Zuckerman on New Breast Implant Rupture Study and MRI's

www.BreastImplantAwareness.org/

www.BreastImplantInfo.org Dr. Zuckerman's site

Dear Friends,

When the FDA approved silicone breast implants in November 2006, the
agency and the companies making implants warned women to undergo
regular breast MRI screenings so that they would know if their
implants were broken or leaking. The warnings tell women to get an
MRI after 3 years, and every other year after that.

Breast MRIs are expensive -- averaging $2,000 -- and not covered by
health insurance. Since the MRI warnings could discourage women from
choosing silicone gel breast implants, it is not surprising that
advertisements for breast implants do not mention MRIs, and many
plastic surgeons have argued that MRIs are not necessary.

A new study published in Plastic and Reconstructive Surgery ("Magnetic
Resonance Imaging and Explantation Investigation of Long-Term Silicone
Gel Implant Integrity"-- see abstract below) concludes that silicone
gel implants are unlikely to rupture until they are in the body at
least 6 years, and that after 13 years only about 12% will be
ruptured. The authors also conclude that MRIs are not necessary to
check for rupture until 15 years, and only every 5 years after that. A
careful review of the study shows that the plastic surgeons who wrote
the article are basing their conclusions on wishful thinking rather
than science.

Two of the authors are familiar names to experts on breast implants;
Nick Collis and David Sharpe are authors of the "Sharpe/Collis" study
that Mentor Corporation submitted to the FDA to prove the long-term
safety of their silicone gel breast implants. The FDA scientists
strongly criticized the Sharpe/Collis study, and their criticisms are
also relevant to this study. In fact, it appears that this study is a
slightly worse version of the study submitted to the FDA.

The first question for a thinking reader is: why is the rupture rate
so much lower than the one reported by FDA scientists Dr. Lori Brown
and her colleagues in 2001? Both studies were of women who had no
idea that their implants might be ruptured. Brown et al found that
most women in their study had at least one ruptured implant, whereas
the new study by Colllis et al found that 14% had at least one
ruptured implant.

There are two likely explanations for this difference, but Collis et
al only focus on one: they believe that the implants in their study --
the kind of Mentor implants popular today -- are sturdier and last
longer than the implants in the Brown study. They are probably
correct -- BUT, that is not the most reasonable explanation for fewer
ruptures. All the women in the Brown et al study had breast implants
for at least 6-7 years and many had implants for more than 15 years;
in the Collis study the minimum age of the implants was 4.8 years, and
the maximum was only 13.5 years. Only one woman in the Collis study
apparently had implants for over 13 years. The average age of
implants was under 9 years.

Think of breast implants like a car tire. At first, most car tires
are fine. Over time, they wear down. Those problems don't increase
gradually from year 1 through year 20. The first few years are
relatively trouble free, but the older your tires and the more you
drive, the more likely the tires are to rupture. The increase in
rupture is exponential after 50,000 miles -- and even more dramatic
for any tires still on the road after 65,000 miles. You can't predict
the percentage of tires that will go flat between 60,000-65,000 miles
based on the percentage going flat between 10,000 and 15,000 miles. In
the same way, you can't predict ruptures between 14-18 years based on
the percentage ruptured between 6-10 years.

It's also important to remember that both the Brown study results and
the Collis study results should be considered underestimates of
rupture for a simple reason: both were "retrospective" studies that
started at a time when women already had their implants for quite a
few years and they eliminated any women whose implants had been
removed before the study was started. In other words, any woman whose
implant was removed in the first 4.5 years (and in many cases, even
longer) was not eligible for the study. In fact, the Collis study
used a database that was started in 1997, based on women who got
implants since 1986 -- 11 years earlier. You'd think the women would
therefore include many women who had implants for at least 11 years,
but it doesn't. Why not? Since so few of the women in the Collis
study had implants for 11 years or more, it seems that many of the
women who had implants for a longer period of time were either
ineligible for the study because their implants had been removed, or
refused to participate (the refusal rate was about 50%. Whether the
implants were removed because of pain, capsular contracture, or other
reasons, it is likely that some of those removed implants were
ruptured.

The Collis et al study tries to study one type of implant (Mentor's
textured silicone implants) since 1986 and all were above the muscle.
Therefore, the results are not relevant to implants placed below the
muscle (which is more common in the U.S. today). In addition, the
implants were relatively small, with approximately half 225 cc in size
or smaller -- much smaller than the typical implant size in the U.S.
today.

The bias of the Collis study interpretation is obvious in their
published article. For example, the authors focus on the percentage
of implants that are ruptured, not the percentage of women with
ruptured implants. There is a big difference: since most women start
out with one ruptured implant, the number of women with ruptured
implants is almost twice as high as the percentage of implants that
are ruptured.

That bias is also obvious in the authors review of previous studies.
They don't even discuss the results of the Brown (FDA) study--
apparently, they don't like those results. They misquote a study of
Holmich et al as finding a 15% rupture rate at 10 years, but actually
what Holmich et al reported was a rupture rate of "at least 15%" --
and again that is 15% of implants but approximately 30% of women. (The
Holmich study was funded by Dow Corning)

The most worrisome part of this published article is the conclusions,
which are not based on data but rather wishful thinking. Even though
less than a dozen women in the study had implants for 13 years or
longer (the authors don't specify how many), the authors conclude that
the rupture rate is 11.8% percent by 13 years. Even though none of
the women in the Collis study had implants for 14 years or more, the
authors conclude that MRIs are not necessary to check for rupture
until the implants are 15 years old, and that MRIs are only needed
every 5 years after that. But, obviously, all these implants could
break in the 14th, 15th, and 16th year, and the plastic surgeons doing
this study would have no way of knowing, since none of the women had
implants that long.

Another important question about the study: if the women in the study
started getting breast implants in 1986, why do none of the women have
implants for more than 14 years when the study is published 21 years
later?

What is also striking is how inaccurate the radiologists were at
reading the breast MRIs in this study. FDA estimates that 86% of
breast MRIs are accurate at determining rupture, but in this study the
accuracy was approximately 67%.

Like most breast implant studies, this study is designed and
interpreted in ways that reflect the financial interests of the
funders and the authors. That's why we call them checkbook science .
Most of these studies have been funded by Dow Corning or plastic
surgeons. In this case, the study was conducted by plastic surgeons
and partially funded by Mentor and also by a Plastic Surgery
Department.

Diana Zuckerman, PhD
National Research Center for Women & Families


Plast Reconstr Surg. 2007 Oct;120(5):1401-6.Click here to read Links
Magnetic resonance imaging and explantation investigation of
long-term silicone gel implant integrity.
Collis N, Litherland J, Enion D, Sharpe DT.

Royal Victoria Infirmary, Newcastle Upon Tyne NE1 4LP, United
Kingdom. nick.collis@nuth.nhs.uk

BACKGROUND: Information about silicone gel implant longevity is
sparse. Magnetic resonance imaging studies have superseded
explantation studies in the search for data on their long-term
integrity. Unfortunately, the majority of studies are based
predominantly on second-generation implant cohorts. Although magnetic
resonance imaging is acknowledged to be the best imaging modality, the
results of any study are entirely dependent on its ability to
differentiate ruptured from intact implants. METHODS: A single,
textured, third-generation implant type was chosen, to reduce the
number of variables. The largest cohort of patients in our database
had subglandular Mentor Siltex gel implants (Mentor Medical Systems,
Santa Barbara, Calif.). They were contacted and offered a magnetic
resonance imaging scan. All patients with at least one radiologically
ruptured implant were then offered explantation. RESULTS: One hundred
forty-nine patients with bilateral subglandular implants (median +/-
SD age, 8.9 +/- 2.3; range, 4.8 to 13.5 years) were imaged and
reported by two independent radiologists. Twenty-three patients were
reported to have 33 radiologically ruptured implants. Twenty-one
patients (30 radiologically ruptured implants) agreed to explantation.
Statistical analysis using maximum likelihood estimation of survival
curve for cross-sectional data suggests that implant rupture starts at
6 to 7 years and that by 13 years approximately 11.8 percent of
implants will have ruptured. CONCLUSION: Although these results cannot
necessarily be extrapolated to other implant types and manufacturers,
they provide further information about the natural history of implant
integrity, better enabling us to counsel prospective and current
implant recipients.

PMID: 17898620 [PubMed - in process]