Abstract

Background

National population information about the surgical treatment rate for primary cancers, including breast cancer, has remained a significant data gap in Canada. This gap has implications for cancer care planning and evaluating health system performance. New linkages between the Canadian Cancer Registry and hospital discharge records were conducted by Statistics Canada in 2016. Using already existing, routinely collected health administrative data, these linkages allow viable reporting of surgical cancer treatment for the first time for all provinces and territories (except Quebec).

Data and methods

Hospital record information about type and date of surgical treatment of tumours was provided by information from linked data. These linked data reported 50,740 incident primary malignant breast tumours diagnosed between January 1, 2010, and December 31, 2012, among females aged 19 years or older. The unadjusted treatment rate for primary surgical intervention within one year was calculated as the proportion of total tumours that were linkable to hospital records.

Results

For three combined years (2010, 2011 and 2012), 88.3% (N=44,780) of patients overall received at least one surgical treatment. Variations to the surgical rate occurred across jurisdictions, with the highest rate at 91-92% for Prince Edward Island, Newfoundland and Labrador, British Columbia and New Brunswick. Generally, there was an inverse gradient between surgical treatment rate and tumour stage.

Interpretation

The surgical treatment rate of new primary breast cancers varied across provinces and territories from 2010 to 2012. New linked data could be used to further identify geographic and demographic inequities in terms of receiving surgical cancer treatment and contribute to the evaluation of cancer system performance and outcomes.

Keywords

Breast cancer, surgical treatment, record linkage, administrative data, disease stage

Findings

Women in Canada are more likely to develop breast cancer than any other type of cancer. The lifetime probability of developing breast cancer (based on 2010 data) is 1 in 8 for women. An estimated 26,300 new cases of breast cancer and 5,000 deaths because of breast cancer were expected to have occurred in 2017. While the number of new breast cancer cases has been increasing, due largely to an aging population and population growth, the age-standardized incidence rate has remained stable. The age-standardized breast cancer mortality rate has been decreasing over time, falling 44% from 41.7 deaths per 100,000 population in 1988 to 23.2 deaths per 100,000 population in 2017. This is likely partly the result of earlier diagnosis through screening and treatment advances. [Full Text]

Authors

Gisèle Carrière(Gisele.carriere@canada.ca) and Claudia Sanmartin are with the Health Analysis Division and Patricia Murison is with the Health Statistics Division at Statistics Canada, Ottawa, Ontario.

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What is already known on this subject?

  • In the Canadian population, trends for age-standardized incidence rates of breast cancer have remained stable and mortality rates for breast cancer have declined.
  • According to Canadian Cancer Statistics 2017, the lifetime probability of developing breast cancer (based on 2010 data) is 1 in 8 for women. An estimated 26,300 new cases of breast cancer were expected to have occurred in 2017.

What does this study add?

  • This is the first study to report the rate of surgical interventions used to treat new primary female breast tumours for all of Canada (except Quebec) based upon hospital administrative data linked to the Canadian Cancer Registry, the gold standard for tumour diagnosis in Canada.
  • Variation in the surgical treatment rate of new primary breast cancers was evidenced across provinces and territories.
  • These results also provide new information about the surgical treatment rate for breast tumours diagnosed at different stages of the disease.

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