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Methodology 7.1.c

Breast Cancer Screening Quality and Efficiency Methodology
Short description of Indicator Percentage of Ontario women (Category B), 30-69 years old, confirmed to be high risk by genetic assessment (counselling and/or testing)
Rationale for measurement

The High Risk Ontario Breast Screening Program (OBSP) program was launched in 2011 as an extension of the OBSP1,4, following guidelines from the Ontario Health Technology Advisory Committee (OHTAC) that women at high risk for breast cancer be screened in a programmatic setting to ensure appropriate quality assurance processes are in place.2

Category B women are those women who do not have a known breast cancer risk and are referred for further assessment to determine their risk status.3 Assessment may be genetic testing or risk assessment.4,5 The percentage of women confirmed to be at high risk after referral for further assessment is a measure of the effectiveness of the referral process.

For women who are determined to be at high risk for breast cancer, MRI in addition to digital mammography is recommended.5

Evidence/references for rationale
  1. Ministry of Health and Long-Term Care. Expansion of the Ontario Breast Screening Program (OBSP) to Include Women Aged 30 to 69 at High Risk for Breast Cancer [Internet]. Toronto: INFOBulletin; 2011 [cited 2017 Nov 29]. Available from:
  2. Health Quality Ontario. Cancer Screening with Digital Mammography for Women at Average Risk for Breast Cancer, Magnetic Resonance Imaging (MRI) for Women at High Risk: An Evidence-Based Analysis. Ontario Health Technology Assessment Series. 2010;10(3):1-55.
  3. Cancer Care Ontario. Ontario breast screening 2011 program report. Toronto ON): Cancer Care Ontario; 2013.
  4. Chiarelli AM, Prummel MV, Muradali D, Maipruz V, Horgan M, Carroll JC et al. Effectiveness of screening with annual magnetic resonance imaging and mammography: results of the initial screen from the Ontario high risk breast screening program. J Clin Oncol. 2014 Jul 20;32(1):2224–30.
  5. Warner E, Messersmith H, Causer P, Eisen A, Shumak R, Plewes D. Magnetic resonance imaging screening of women at high risk for breast cancer. Toronto (ON): Program in Evidence-Based Care (PEBC), Cancer Care Ontario; 2012 Aug.
Calculations for the indicator (Total number of Ontario women, age 30 to 69, confirmed to be at high risk by genetic assessment (counselling and/or testing) / Total number of Ontario women, age 30 to 69, who completed genetic assessment) x100 = Percentage women confirmed high risk
Standardized Rate Calculation N/A
Unit Percentage (%)
Data sources
  • ​ICMS (Integrated Client Management System) - OBSP genetic assessment, high risk confirmation and high risk screens
  • PCCF+, version 6D - Residence and socio-demographic information
Time Frame 2013 - 2016
Geographic Scale
  • ​Provincial (Ontario)
  • LHIN of residence
Denominator description Total number of Ontario women, age 30 to 69, who completed genetic assessment
  • Women (category B), 30 to 69 years old, who completed genetic assessment
  • Category B is defined as women who are referred to genetic assessment to determine their eligibility for the High Risk OBSP
  • Age is based on the OBSP registration date
  • Women with a valid date per below criteria were included:
    • Women with a valid OBSP registration date (date the high risk referral information was entered) AND
    • Women with a valid initial primary care provider visit date AND
  • Women with a valid genetic counselling date and genetic testing date
  • LHIN assignment was determined using PCCF+, version 6D; residential postal code was used to identify LHIN


  • Women with a missing or invalid HIN, date of birth, postal code or LHIN
  • Women who completed genetic assessment but for whom eligibility is unknown
Numerator description Total number of Ontario women, age 30 to 69, confirmed to be at high risk by genetic assessment (counselling and/or testing)
  • Women, 30 to 69 years old, confirmed high risk
  • Confirmation date of high risk status for women referred to genetic assessment (Category B) is defined as the most recent of either the genetic assessment date or the update date (update date is selected only if it is before the High Risk OBSP screening episode date)
Considerations  Women can be referred to genetic assessment at age 29, but cannot be screened in the OBSP high risk program until age 30 (or 10 weeks short of their 30th birthday)
Data availability & limitations There is up to a year reporting lag for this indicator as data are based on the registration date (date the requisition form data were entered into the ICMS). Women may take up to one year from being referred to the High Risk OBSP to completion of genetic assessment
CSQI Year 2018