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

CANCER INCIDENCE AND CAUSE-SPECIFIC MORTALITY AMONG CANADIAN WOMEN WITH COSMETIC BREAST IMPLANTS Lin Xie Surveillance Division Centre for Chronic Disease Prevention and Control Public Health Agency of Canada NAACCR Annual Conference 2009 San Diego, California June 16-18, 2009

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

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

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

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

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

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

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)

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

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

Results for Cancer Incidence

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

Standardized Incidence Ratios (SIR) for Selected Cancers among Implant Patients

Standardized Incidence Ratios (SIR) for Selected Cancers among Control Cohort

Relative Risks (RR) of Cancer Incidence for Breast Implant vs. Control Patients

Relative Risks (RR) of Breast Cancer for Selected Implant Surgery Characteristics, Compared to Other Plastic Surgery Patients

Relative Risks (RRs) of Breast Cancer for Selected Breast Implant Characteristics

Relative Risks (RR) of Breast Cancer for Selected Implant Characteristics, by Site of Implantation

Results for Cause-specific Mortality

Standardized Mortality Ratios (SMRs) among Breast Implant Patients

Standardized Mortality Ratios (SMRs) among Plastic Surgery Patients

Mortality experience of Augmented Women Compared to Other Plastic Surgery Patients

Standardized Mortality Ratios (SMRs) for Suicides among the Cohort Relative to the General Population

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

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

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

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.

Thank You

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