Notes on Canadian Task Force on Preventive Health Care: Breast Cancer Screening for Ages 40-49

Introduction

• Breast Cancer Screening: A personal choice for women aged 40 to 74.
• Information Provided: Benefits and harms of screening to align with values and preferences.
• Mammography Screening: Offered every 2 to 3 years if screening is desired.

Recommendations for Ages 40-49

• Current Evidence: Suggests not to systematically screen with mammography.
• Conditional Recommendation: Very low certainty; variable in individual preference.
• Screening Offered: For women who want to be screened after understanding benefits and harms.

Breast Cancer Screening for Women Not at High Risk

• Target Audience: Women with average or moderately increased risk, excluding those with personal/family history or genetic risks.
• Supplemental Screening: Not recommended for MRI or ultrasound due to lack of evidence on benefits.

Benefits and Harms

• Ages 40-49: Harms possibly outweigh benefits.
• Systematic Review: Majority may not find benefits exceed harms; variability in patient values and preferences.
• Race and Ethnicity: Variability observed but lack of data on benefits/harms.

Risk Considerations

• Moderate Risk: Family history or high breast density may increase risk; no strong evidence for supplemental screening.
• Family History Definition: One first-degree or two second-degree relatives diagnosed after age 50.

Screening Outcomes Over 10 Years

• No Screening:
  • 983 not diagnosed with breast cancer
  • 17 will be diagnosed; 2 will die from breast cancer
• With Screening:
  • 613 screened negative; 368 will have more tests
  • 981 not diagnosed; 19 diagnosed
  • 1-2 breast cancer deaths prevented

Lifetime Screening Benefits and Harms

• Screening Start Age: Comparison between starting at age 40 vs. 50
  • Less chemotherapy needed if starting at age 40
• Overdiagnosis and Tests: More tests without cancer diagnosis, including biopsies.

Family History and Breast Density

• Family History: Up to 1.5 in 1000 breast cancer deaths prevented.
• Breast Density: Up to 1.8 in 1000 deaths prevented; no supplemental screening recommended.

Ethnicity and Screening

• Lack of Evidence: No ethnicity-specific recommendations due to insufficient data.
• Epidemiological Insights:
  • Median age of diagnosis younger for non-White individuals.
  • Differences in incidence and mortality rates for ethnic groups.

Systemic Factors

• Racism and Health Disparities: Recognized as contributing to inequities in breast cancer outcomes.

Conclusion

• Open Discussion Encouraged: About benefits and harms of screening, considering individual preferences and risks.
• Tools and Resources: Available at the Canadian Task Force website.