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 . 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
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