ANSWERS
06/28/1995

<TITLE>TDA AND POLYURETHANE BREAST IMPLANTS</TITLE>
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T95-31                                         Susan M. Cruzan
June 28, l995                                  (301) 443-3285


              TDA AND POLYURETHANE BREAST IMPLANTS

     FDA is receiving inquiries about final results of a study 
of cancer risks associated with polyurethane foam-covered breast
implants.  About 110,000 women have these implants, which are
filled with silicone gel.  The study, designed by FDA and Bristol-
Myers Squibb Co. of New York, N.Y., focused on TDA (2,4-
toluenediamine), a chemical released from polyurethane foam that
has been linked to cancer in laboratory animals.  The following may
be used to answer inquiries.  
     The study showed that the risk of cancer from TDA released by
polyurethane breast implants is negligible.  FDA estimates it is
unlikely that exposure to TDA will cause cancer in even one of the
women with these implants.  The health risk connected with surgical
removal of the implants is far greater than the risk of developing
cancer.     
      The study was initiated after an FDA analysis in April l991
showed that it was possible for polyurethane foam to break down
under human body conditions to form TDA.  As a result of the 1991
finding, Surgitek, a former subsidiary of Bristol-Myers Squibb
immediately suspended sales of the polyurethane-coated implants, 
                             -MORE-
                                               Page 2,  T95-31, TDA
Meme and Replicon, from the market.  The company also was required
to conduct a study to measure levels of TDA in body fluids of women
with the implants.   
     In August l991, FDA's General and Plastic Surgery Devices
Panel concluded that the estimated TDA-associated lifetime cancer
risk was likely to be very small but that additional studies were
needed to assess the risk more precisely. 
     The Bristol-Myers Squibb study compared TDA in urine from 61
women with the implants with the levels of the same chemical in 61
women without implants.  Using a highly sensitive test method,
scientists found negligible amounts of "free" TDA in the urine of
about 80 percent of the women with the implants. 
      Free TDA in even smaller amounts was occasionally found in
samples from about 13 percent of the women without implants,
suggesting that the environment may also be a source of TDA
exposure.  Blood serum was tested but the data were not used
because loss of TDA could occur during separation of serum from
blood.    
     Based on the study in women who had the implants, FDA
estimates that the risk of cancer from exposure to TDA is about one
in one million over a woman's lifetime.   Therefore, the results of
the study support FDA's original recommendation that women with
polyurethane foam-covered breast implants who are not experiencing
problems should not have them removed based solely on concern about
cancer from exposure to TDA. 
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