Trends in mammography, hormone replacement therapy, and breast cancer incidence and mortality in Canadian women
- 34 Downloads
The purpose of the study is to examine relationships between long-term trends of region- and age-specific rates of mammography, hormone replacement therapy (HRT), and breast cancer incidence and mortality in Canadian women aged 35 years and older.
Population-based complex surveys were used to estimate mammography use in the past 2 years and ever, and HRT use in the past month. National population-based administrative data were used to estimate breast cancer incidence and mortality. Joinpoint analyses were used to estimate trends in rates and years where trend changed.
No consistent relationship between mammography use and breast cancer incidence was observed across age groups. Opportunistic screening occurred prior to the establishment of organized screening programs in Canada and prior to substantial declines in breast cancer mortality observed around 1990. Women aged 35–39 years demonstrated a 62.8% relative decrease in breast cancer mortality between 1950 and 2015 despite lower rates of mammography use in the past 2 years (range 9.4–15.9%) reinforcing important treatment advances. A substantial proportion of women in their 40s report mammography use in the past 2 years (range 35.8–42.2%) and regional variation exists reflecting inconsistencies in guidelines across Canada.
Rates of mammography use over time do not necessarily reflect national guideline releases or establishment of organized screening programs.
KeywordsMammography Hormone replacement therapy Breast cancer Incidence Mortality
Both authors contributed to study design, interpretation of results, drafting the manuscript, critical revisions, and approval of the final manuscript. D.Z. performed the analyses.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
- 1.Canadian Cancer Society’s Advisory Committee on Cancer Statistics (2017) Canadian cancer statistics 2017. Canadian Cancer Society, Toronto (ON). http://cancer.ca/Canadian-Cancer-Statistics-2017-EN. Accessed 11 July 2017
- 2.Canadian Task Force on the Periodic Health Examination (1979) The periodic health examination. CMAJ 121:1193–1254Google Scholar
- 3.Canadian Task Force on the Periodic Health Examination (1986) The periodic health examination: 2. 1985 update. Can Med Assoc J 134:724–729Google Scholar
- 4.Canadian Task Force on the Periodic Health Examination (1994) The Canadian guide to clinical preventive health care. Canada Communication Group—Publishing, OttawaGoogle Scholar
- 7.Canadian Partnership Against Cancer (2016) Breast cancer screening in Canada: monitoring and evaluation of quality indicators—Results Report, January 2011 to December 2012. Canadian Partnership Against Cancer, Toronto. https://content.cancerview.ca/download/cv/prevention_and_screening/screening_and_early_diagnosis/documents/breast_cancer_screening_canada_monitoring_evaluating_report_2011_12p?attachment=0. Accessed 8 April 2018
- 17.Coldman A, Phillips N, Wilson C, Decker K, Chiarelli AM, Brisson J, Zhang B, Payne J, Doyle G, Ahmad R (2015) Pan-Canadian study of mammography screening and mortality from breast cancer. J Natl Cancer Inst 106(11). https://doi.org/10.1093/jnci/dju261
- 18.Gotzsche PC, Jorgensen KJ (2013) Screening for breast cancer with mammography. Cochrane Database Syst Rev 6:CD001877Google Scholar
- 21.International Rules for Multiple Primary Cancers (ICD-O Third Edition) (2004) Internal Report No. 2004/02. IARC, Lyon. http://www.iacr.com.fr/images/doc/MPrules_july2004.pdf. Accessed 1 June 2017
- 22.World Health Organization (1977) International classification of diseases, ninth revision. World Health Organization, GenevaGoogle Scholar
- 23.International Classification of Diseases for Oncology, 3rd edition, 1st revision (ICD-O-3.1) (2017). International Agency for Research on Cancer, Lyon, France. http://codes.iarc.fr/abouticdo.php. Accessed 16 Feb 2017
- 24.World Health Organization (1992) International statistical classification of diseases and related health problems, Tenth Revision. World Health Organization, GenevaGoogle Scholar
- 25.Statistics Canada. CANSIM database: Table 051-0001: Estimates of population, by age group and sex for July 1, Canada, provinces and territories, released September 27, 2017. http://www5.statcan.gc.ca/cansim/a26?lang=eng&retrLang=eng&id=0510001&&pattern=&stByVal=1&p1=1&p2=-1&tabMode=dataTable&csid=. Accessed 6 October 2017
- 26.Jensen OM, Parkin DM, MacLennan R, Muir CS, Skeet RG (eds) (1991) Cancer registration: principles and methods. International Agency for Research on Cancer, Lyon, FranceGoogle Scholar
- 28.Joinpoint Regression Program, version 126.96.36.199—June 2015; Statistical Methodology and Applications Branch, Surveillance Research Program, National Cancer InstituteGoogle Scholar
- 32.International Agency for Research on Cancer (IARC) (2016) Breast cancer screening, vol 15. IARC Handbooks of Cancer Prevention. IARC, Lyon, FranceGoogle Scholar
- 33.Report from the Evaluation Indicators Working Group (2013) Guidelines for monitoring breast cancer screening program performance, 3rd edn. Canadian Partnership Against Cancer, TorontoGoogle Scholar
- 37.National Center for Health Statistics (2017) Health, United States, 2016: With Chartbook on Long-term Trends in Health. National Center for Health Statistics, HyattsvilleGoogle Scholar