CANCER INCIDENCE AND CAUSESPECIFIC MORTALITY AMONG CANADIAN WOMEN WITH COSMETIC BREAST IMPLANTS

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CANCER INCIDENCE AND CAUSE-SPECIFIC MORTALITY
AMONG CANADIAN WOMEN WITH COSMETIC BREAST
IMPLANTS

• NAACCR Annual Conference 2009
• San Diego, California
• June 16-18, 2009

Lin Xie Surveillance Division Centre for Chronic
Disease Prevention and Control Public Health
Agency of Canada
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Study Team

• Drs Jacques Brisson and Louis Latulippe - Laval
  University, Quebec
• Dr. Eric J. Holowaty, Cancer Care Ontario
  University of Toronto, Ontario
• Dr. Paul J. Villeneuve, University of Toronto
• Drs. Yang Mao and Anne-Marie Ugnat, and Lin Xie -
  Public Health Agency of Canada

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Background

• The demand for cosmetic breast augmentation has
  increased in recent years. An estimated 100,000
  to 200,000 women in Canada have breast implants,
  approximately 80 for cosmetic breast
  augmentation and 20 for cosmetic reconstruction
  after mastectomy or to correct under- or
  non-developed breasts
• In the United States, approximately 4 million
  women, more than 3 of the female population,
  have breast implants
• In 2006, breast augmentation was the most
  commonly performed cosmetic surgery procedure in
  the US with an estimated 329,000 procedures. This
  represents an increase of over 300 in the past
  decade

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Background

• Furthermore, the number of Canadian and American
  women who undergo cosmetic breast augmentation is
  expected to increase, given the decision of
  Health Canada and the US Food and Drug
  Administration in 2006 to reapprove silicone
  gel-filled breast implants for general cosmetic
  use
• There is widespread concern about the possible
  long-term health effects among women who have
  received breast implants for cosmetic purposes

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Objectives

• This study, the largest cohort study undertaken
  to date, examined the cancer and cause-specific
  mortality in a cohort of 24,558 women with breast
  implants and 15,893 women who underwent other
  cosmetic procedures in Ontario and Quebec between
  1974 and 1989

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Methods Study Population

• Among women, ages 18, who were residents of ON
  and QC, and who received the cosmetic surgeries
  in 1974-1989,
• Exposed population
• Those who received bilateral cosmetic breast
  implants
• Type of fills silicone gel filled (SGFI),
  saline, saline and silicone combined
• Type of envelopes silicone and polyurethane
• Comparison population
• Those who received other cosmetic surgeries at
  the same practices
• Eligible procedures chemical peel, coronal brow
  lift, otoplasty, rhinoplasty, rhytidectomy, or
  blepharoplasty

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Methods Study Population

• Plastic surgery patients were frequency matched
  to the breast implant recipients by
• year of entry into the cohort, and
• surgeon
• Exclusion Criteria
• Had previous breast surgery
• Received other types of silicone or artificial
  implants
• Received substantial doses of silicone
• Had a history of cancer prior to index surgery
• Had a male genotype

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Methods Study Population

• After using the exclusion criteria,
• Exposed population 24,558 women (7,153, ON and
  17,405, QC)
• Comparison population 15,893 patients (4,418,
  ON and 11,475, QC)

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Methods Study Population

• Case ascertainment
• Incidence cases of cancer were identified through
  record linkage of the personal identifying
  information of the cohort to that in Canadian
  Cancer Registry
• The mortality experience of the cohort was
  ascertained through record linkage to the
  Canadian Mortality Database
• End of follow-up December 31, 1997
• The proportion of all cancers and breast cancers
  that were confirmed histologically was 82 and
  93, respectively

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Methods Statistical Analysis

• Cancer incidence and mortality of augmented women
  were compared to the general population using
  standardized incidence and mortality ratios (SIRs
  and SMRs)
• Comparisons between implant patients to surgical
  controls were performed using Poisson regression
• Stratified analyses were also conducted to
  examine cancer risks and mortality across implant
  and surgery characteristics of the implant
  population
• The comparisons were done for patients with one
  or more year of follow-up

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Results for Cancer Incidence
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Results

• The median ages at surgery were 31.3 for implant
  group, and 31.9 for control group. Over half of
  the implants were received by women between the
  ages of 25 and 34
• More than 70 of the women in the implant and
  control cohorts were followed for at least 10
  years
• The length of follow-up was longer among Quebec
  implant patients (15.4 years), relative to their
  Ontario counterparts (13.8 years)
• The majority of women (80) received implants
  that were filled with silicone

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Standardized Incidence Ratios (SIR) for Selected
Cancers among Implant Patients
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Standardized Incidence Ratios (SIR) for Selected
Cancers among Control Cohort
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Relative Risks (RR) of Cancer Incidence for
Breast Implant vs. Control Patients
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Relative Risks (RR) of Breast Cancer for Selected
Implant Surgery Characteristics, Compared to
Other Plastic Surgery Patients
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Relative Risks (RRs) of Breast Cancer for
Selected Breast Implant Characteristics
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Relative Risks (RR) of Breast Cancer for Selected
Implant Characteristics, by Site of Implantation
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Results for Cause-specific Mortality
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Standardized Mortality Ratios (SMRs) among Breast
Implant Patients
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Standardized Mortality Ratios (SMRs) among
Plastic Surgery Patients
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Mortality experience of Augmented Women Compared
to Other Plastic Surgery Patients
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Standardized Mortality Ratios (SMRs) for Suicides
among the Cohort Relative to the General
Population
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Conclusions

• Comparisons to the general population indicated
  significantly reduced rates of cancer for all
  sites combined and breast cancer in both the
  implant and other surgery cohorts
• Overall cancer incidence rates were similar
  between the implant and other plastic surgery
  patients. However, augmented women had lower
  breast cancer rates than the plastic surgery
  patients
• Women who received breast implants had a lower
  mortality risk than the general population, and a
  risk similar to women who received other cosmetic
  surgeries

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Conclusions

• In contrast, both the breast implant and other
  surgery patients had higher suicide rates
• No differences in mortality were found between
  the implant and other surgeries group for any of
  the 20 causes of death examined
• Serious consideration should be given to
  providing consultation for patients who are
  considered by the plastic surgeon to be at high
  risk for psychiatric disorder or suicide

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Next Steps

• To evaluate risk factors for suicide among women
  who undergo cosmetic surgery
• To determine whether cosmetic implants impair the
  early detection of breast cancer and adversely
  influence survival
• Although the women were followed up to 24 years,
  given that most received implants at a relatively
  young age and that, in general, the risk of
  cancer increases with age, continued follow-up
  and analysis of this cohort is recommended

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Acknowledgements

• We are especially grateful to the participation
  of the plastic surgeons in Ontario and Quebec,
  and for the opportunity to access provincial
  cancer registry data. We thank Drs. Louise
  Duranceau, Pierre Langlois, Walter Peters and
  Sylvie Bérubé, and Ms. Gemma Lee, for their
  support in the study design and data collection.
  We thank Drs Louise Brinton and Anthony Miller
  for their comments on an earlier draft of the
  incidence paper. Finally, we thank the
  Occupational Health and Research Division at
  Statistics Canada for linking the cohort to the
  national cancer registry and vital statistics
  databases.

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• Thank You