Organized Breast Cancer Screening Programs in Canada - Report on Program Performance in 2001 and 2002

Executive Summary

Although mortality has declined over the past decade, breast cancer continues to be the most common cancer afflicting Canadian women with 21,600 new cases estimated for 2005. According to 1998 estimates, breast cancer cost Canadians more than $1 billion in terms of the value of years of life lost due to premature death. Nationally, the majority of new cases of breast cancer occur among women aged 50 to 69. Early detection through organized breast cancer screening combined with effective treatment remains the best option currently available to reduce breast cancer deaths among women in this age group.

The goal of monitoring and evaluating organized breast cancer screening programs in Canada is to promote high-quality screening, leading to reductions in breast cancer mortality and morbidity, while keeping potential harms of screening to a minimum. This document presents an evaluation of the performance of organized breast cancer screening programs in Canada for the 2001 and 2002 calendar years using data submitted to the Canadian Breast Cancer Screening Database (CBCSD) by 10 provinces. Currently none of the three territories provide evaluation data to the CBCSD. Although most national performance targets were met or exceeded, the present evaluation suggests a number of areas on which ongoing improvement efforts should focus in order to further the aim of reducing the burden of breast cancer.

The capacity to meet the demand for breast screening is one aspect of program delivery that continues to be a challenge for organized screening programs. Although most programs saw increased participation in 2001 and 2002, only 33.9% of eligible women accessed organized screening nationally, leaving the target of at least 70% participation among women aged 50 to 69 unmet. Although program expansion and improved recruitment will bring the benefits of organized screening to more Canadian women, several mature programs are reaching the limits of their capacity at a plateau of approximately 50% participation.

Monitoring and evaluation efforts, using the CBCSD, are used to enhance the performance of screening across Canada.

For women requiring diagnostic follow-up, there must be adequate staffing and facilities for diagnosis and treatment. In recent years, abnormal call rates (i.e. the proportion of women who are recalled for further diagnostic assessment) have increased to the point that the target for abnormal call rates in 2001 and 2002 was no longer being met. Abnormal call rates need to be optimized in order to reduce potential harms of screening for healthy women (e.g. unnecessary diagnostic procedures and the anxiety associated with them) while maintaining high cancer detection rates. Programs undergoing expansion must pay particular attention to the additional training needs of personnel new to organized screening programs. In spite of the challenge of a substantial increase in the volume of women undergoing assessment from 14,837 in 1999 to 50,133 in 2002, wait times for diagnostic tests improved slightly during this period. However, most targets for timely diagnostic follow-up, particularly for women requiring a biopsy for diagnosis, remain unmet. A more detailed discussion of actions taken to reduce wait times and the progress achieved towards meeting targets is the subject of the Special Topic of this report.

Organized screening programs aim to maximize the benefits to participants by detecting as many cancers as possible as early as possible. The number of invasive breast cancers detected among screened women (invasive cancer detection rate), the proportion of invasive cancers that are small, and the proportion of invasive cancers that have not spread to the lymph nodes reflect the extent to which programs are achieving this goal. Canadian performance targets for invasive cancer detection rates were met. Screening programs were effective in finding breast cancers at an early stage, often before they could be felt or had spread to the lymph nodes.

In the coming years, organized screening programs will continue to strive to provide high-quality breast cancer screening. Programs aim to achieve reductions in breast cancer mortality in the target population by conducting research to enhance the quality and effectiveness of screening, and by adapting and enhancing their practices as new evidence and technologies become available. The results of monitoring and evaluation efforts, such as those reported here, are used by governments, cancer agencies, screening program managers, front-line health professionals, and other breast cancer stakeholders to enhance the performance of screening across Canada.

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