17 janvier 2006 19:16
STUDY: Cancer incidence in a cohort of Ontario and Quebec women having bilat
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From: m keeling
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Sent: Tuesday, January 17, 2006 3:12 PM
Subject: Fw: STUDY: Cancer incidence in a cohort of Ontario and Quebec women having bilateral breast augmentation.
The largest study of breast implanted women to date (see abstract in e-mail below) has just been published on-line. This Canadian study was started in 1996. Some of the more interesting statements in the body of the research states:
(1) Silicone has been shown to be immunogenic.(Silicone Breast Implants: Immunotoxic and Epidemiologic Issues - 1995)
(2) This is the largest breast implant cohort study conducted to date with some women followed up to 24 years.
(3) Canada is one of the few nations whose entire population has been covered by cancer registration.
(4) On average, the length of follow-up was longer among Quebec implant recipients (15.4 years), relative to their Ontario Counterparts (13.8) years.
(5) Among the implant cohort, few Ontario women received breast implants that were coated in polyurethane (<1%), whereas 14% of women in Quebec received such implants. Virtually, all of these polyurethane-coated implants were received between 1985 and 1989. However, 24% did not know whether their implants had a polyurethane coating.
(6) Table IV indicates for implanted patients the observed cases of cancer versus the control patients (those without implants) and the expected cases in the general population are as follows:
Implant patients Control patients Internal comparison
Cancer site Obs. Exp. Obs. Exp.
cases cases SIR cases cases SIR RR
Pancreas 15 12.3 1.22 15 11.3 1.33 0.94
Lung 96 87.9 1.09 81 73.1 1.11 0.93
Malignant
melanoma 33 25.6 1.29 13 16.4 0.79 1.69
(7) An elevated risk of breast cancer was observed among those women who received subglandular breast implants coated with polyurethane relative to those with no such coating (RR = 1.99); however, this result was based on only 15 incident breast cancers.
(8) More than 70% of the cohort members were followed for at least 10 years.
(9) As with previous investigations, we found lower breast cancer incidence rates among women who received breast implants. Several biological mechanisms have been suggested in which the implant procedure itself may confer a lower risk of breast cancer. These include: an enhanced immune system as a result of receiving a breast implant, whereby carcinogens and transformed cells are more easily destroyed; the weight and volume of the implant compresses the glandular tissue resulting in a decreased blood supply that may reduce the rate of cell proliferation; and a long-term metabolic rate resulting from lower temperature of the breast tissue. However, we feel it is more likely that other characteristics contributed to the observed differences in breast cancer rates between women who received implants and the other surgical patients.
(10) Of 133 plastic surgeons potentially eligible, only 51 (38%) permitted access to all of their records (the number of patients recruited in Ontario was substantially lower than originally planned).
(11) When we restricted our analyses to women with subglandular implant placement, those with a polyurethane-coated implant had a statistically significant 2-fold increase in risk relative to women with no such coating.
(12) Previous work suggests that the devices (polyurethane) themselves do not produce sufficient TDA levels to cause breast cancer. Specifically, urine analyses of approximately 110,000 women who received polyurethane foam coated implants found that TDA levels were at such low levels that the associated risk of developing cancer from these implants was estimated to be about 1 in 1 million (Measurement of 2,4 toluenediamine in urine and serum samples from women with Meme or Replicon breast implants - 1997).
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Int J Cancer. 2005 Dec 27; [Epub ahead of print] |
Cancer incidence in a cohort of Ontario and Quebec women having bilateral breast augmentation.
Brisson J, Holowaty EJ, Villeneuve PJ, Xie L, Ugnat AM, Latulippe L, Mao Y.
Department of Social and Preventive Medicine, Laval University, Laval, QC, Canada.
The possibility that women, who receive breast implants for cosmetic purposes, have increased long-term risks of developing cancer continues to be debated. The objective of our study was to prospectively examine cancer incidence among women who received breast implants. A cohort was assembled of 24,558 women, 18 years of age and older, who underwent bilateral cosmetic breast augmentation, and 15,893 women who underwent other cosmetic procedures in Ontario or Quebec between 1974 and 1989. These plastic surgery patients were selected from the same clinics as the implant population. Incident cancers were identified by linking to Canadian registry data up to December 31, 1997. In total, 676 cancers were identified among women who received breast implants compared to 899 expected based on general population rates (standardized incidence ratio (SIR) = 0.75; 95% confidence interval (CI) = 0.70-0.81). Overall cancer incidence rates among women who received breast implants were similar to that of the other plastic surgery patients (relative risk (RR) = 0.91, 95% CI = 0.81-1.02). However, women who received breast implants had lower breast cancer rates than the plastic surgery patients (RR = 0.64, 95% CI = 0.53-0.79). No increased risks were observed among the implant population for any of the other cancer sites examined. Comparisons involving only women who received breast implants found no association between long-term breast cancer incidence and implant site (submuscular vs. subglandular), fill (saline vs. silicone) or envelope (polyurethane-coated or not). In conclusion, women undergoing cosmetic breast augmentation do not appear to be at an increased long-term risk of developing cancer. (c) 2005 Wiley-Liss, Inc. PMID: 16381020 [PubMed - as supplied by publisher]
