Breast Cancer Screening (Mammogram) Participation Methodology

Breast Cancer Screening (Mammogram) Participation
Short description of Indicator	Age-adjusted percentage of Ontario screen-eligible women, 50 to 74 years old, who completed at least 1 mammogram within a 30-month period
Rationale for measurement	There is strong evidence from clinical trials that breast cancer screening can reduce breast cancer mortality.^[1] Observational evidence indicates that widespread adoption of mammography screening has contributed to a decline in mortality from breast cancer.^[1] Adequate participation in breast cancer screening is essential for reductions in mortality to occur in the Ontario population.^{[2] [3] [4]}
Evidence/references for rationale	Nelson H, Fu R, Cantor A, Pappas M, Daeges M, Humphrey L. Effectiveness of breast cancer screening: Systematic review and meta-analysis to update the 2009 U.S. Preventive Services Task Force Recommendation. Ann Intern Med. 2016;164:244–255. doi: 10.7326/M15-0969. Canadian Partnership Against Cancer. Breast Cancer Screening in Canada: Monitoring and Evaluation of Quality Indicators- Results Report, December 2009–January 2010. Toronto (ON): Canadian Partnership Against Cancer; 2015. Canadian Partnership Against Cancer. Report from the Evaluation Indicators Working Group: Guidelines for Monitoring Breast Cancer Screening Program Performance (3rd Edition). Toronto: Canadian Partnership Against Cancer; February, 2013. Coldman A, Phillips N, Wilson C, Decker K, Chiarelli A, Brisson J et al. Pan-Canadian study of mammography screening and mortality from breast cancer. J Natl Cancer Inst. 2014 Oct 1;106(8): pii: dju261. Erratum in: J Natl Cancer Inst. 2015 Jan;107(1):dju404.
Calculations for the indicator	(Total number of Ontario screen-eligible women, 50 to 74 years old, who completed at least 1 mammogram in a given 30-month period/ Total number of Ontario screen-eligible women, 50 to 74 years old in the reporting period) X 100
Standardized Rate Calculation	2011 Canadian population
Unit	Percentage (%)
Data sources	ICMS (Integrated Client Management System) - OBSP mammograms OHIP CHDB (Claims History Database) - Non-OBSP mammogram and mastectomy claims OCR (Ontario Cancer Registry) - Invasive and in-situ breast cancers RPDB (Registered Persons Database) – Demographics PCCF+ - Residence and socio-demographic information
Time Frame	2010 - 2017
Geographic Scale	Provincial (Ontario)
Denominator description	Total number of Ontario screen-eligible women, 50 to 74 years old, in the reporting period Ontario screen-eligible women ages 50 to 74 at the index date Index date was defined as the midpoint in the reporting period, e.g., January 1, 2016 for 2016-2017 All mammograms in ICMS were counted, including those with partial views The 2011 Canadian population was used as the standard population for calculating age-standardized rates Exclusions: Women with a missing or invalid HIN, date of birth, postal code or LHIN Women with a prior diagnosis of invasive or in-situ breast cancer before January 1 of the reporting period; prior diagnosis of breast cancer was defined as: ICD-O-3 codes: C50, a morphology indicative of ductal carcinoma in-situ or invasive breast cancer, microscopically confirmed with a path report Women with a mastectomy before January 1 of the reporting period. Mastectomy was defined in OHIP by fee codes E505, E506, E546, R108, R109, and R117
Numerator description	Total number of Ontario screen-eligible women, 50 to 74 years old, who have completed at least 1 mammogram in a given 30-month period Identifying mammograms: OBSP mammograms for screening purposes were identified in the Integrated Client Management System (ICMS) Non-OBSP mammograms were identified using fee codes in OHIP: X178 (screening bilateral mammogram) X185 (diagnostic bilateral mammogram) Each woman was counted once regardless of the number of mammograms performed in a 30-month period; if a woman had both a program and non-program mammogram within a 30-month period, the program status was selected
Considerations	A small proportion of mammograms performed outside of OBSP as diagnostic tests could not be excluded from the analysis
Data availability & limitations	Historical RPDB address information is incomplete; therefore, the most recent primary address was selected for reporting, even for historical study periods CHDB code X178 for screening bilateral mammography was introduced in October 2010 CHDB code X185 was used for both screening and diagnostic mammography prior to October 2010; since October 2010, X185 has been used for diagnostic mammography only; however, some screening mammograms after October 2010 may still use X185 for claims