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De and colleagues recently reported on a retrospective study to evaluate use of hormone therapy (HT) and breast cancer incidence among Canadian women from 2001 to 2006 [1]. Data for reported HT use from 1996 to 2006 among approximately 1200 women 50–69 years of age were obtained from the National Health Population Survey, confirmed by HT prescription rates in a national pharmacy database, and extrapolated to represent the Canadian female population. The Canadian Cancer registry provided age-standardized breast cancer incidence rates and mammography rates were gleaned from the Canadian Community Health Survey. These data revealed a decline in HT use from 2001 to 2006 (from 11.6 million to 8.5 million prescriptions), with the largest reduction occurring from 2002 to 2003. HT use decreased for all types: estrogen only, progestin only, and estrogen–progestin combined products (data for women using non-combined estrogen plus progestin were not available). Combined product use declined most among women aged 50–69 years from 2002 to 2004, from 12.7% (95% confidence interval (CI) 10.1–14.2%) to 4.9% (95% CI 3.4–6.8%). The overall greatest decline in HT use occurred from 2000 to 2006, with an average decline of -7.6% per year (95% CI -5.9 to -8.9%). Incident breast cancer among Canadian women over 40 years of age peaked in 2002, declined from 2002 to 2004, and then rose again from 2004 to 2006. Among women aged 50–69 years, incidence fell by -9.6% from 2002 to 2004, from 296.3 per 100,000 in 2002 (95% CI 290.8–300.5 per 100,000) to 268.0 per 100,000 in 2004 (95% CI 263.3–273.5 per 100,000). Breast cancer incidence rose again among women aged 50–69 years by 4.5% annually from 2004 to 2006 (95% CI 3.1–7.2%). Mammography rates for women in the 50–69-year age group increased from the late 1990s to 2000 and then remained stable at about 72%.


  • Ivy M. Alexander
    Professor and Director, Adult, Family, Gerontological, and Womens Health Primary Care Specialty, Yale University, New Haven, CT, USA


  1. De P, Neutel CI, Olivotto I, Morrison H. Breast cancer incidence and hormone replacement therapy in Canada. J Natl Cancer Inst 2010;102:1489-95.
  2. Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Womens Health Initiative randomized controlled trial. JAMA 2002;288:321-33.
  3. Jemal A, Ward E, Thun MJ. Recent trends in breast cancer incidence rates by age and tumor characteristics among US women. Breast Cancer Res 2007;9:R28.
  4. Ravdin PM, Cronin KA, Howlander N, et al. A sharp decrease in breast cancer incidence in the United States in 2003, abstract. Paper presented at 29th Annual San Antonio Breast Cancer Symposium; Dec 14, 2006, San Antonio, Texas, USA
  5. Ravdin PM, Cronin KA, Howlader N, et al. The decrease in breast-cancer incidence in 2003 in the United States. N Engl J Med 2007;356:1670-4.
  6. Clarke CA, Glaser SL, Uratsu CS, et al. Recent declines in hormone therapy utilization and breast cancer incidence: clinical and population-based evidence. J Clin Oncol 2006;24:e49-50.
  7. Glass AG, Lacey JV Jr, Carreon JD, Hoover RN. Breast cancer incidence, 19802006: combined roles of menopausal hormone therapy, screening mammography, and estrogen receptor status. J Natl Cancer Inst 2007;99:1152-61.
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