What are the guidelines for breast screening in British Columbia (BC), Canada?

Breast Cancer Screening Guidelines in British Columbia, Canada

In British Columbia, Canada, women aged 40-74 should undergo regular mammography screening, with annual screening recommended for ages 40-54 and biennial screening for ages 55-74, as long as they have a life expectancy of at least 10 years. 1

General Screening Recommendations by Age Group

Women Aged 40-49

• Mammography screening should begin at age 40
• Annual screening is recommended for this age group due to faster-growing tumors in younger women 1
• Digital breast tomosynthesis (DBT) is preferred over standard digital mammography due to decreased recall rates 1
• Women should be informed about both benefits (early detection, less aggressive therapy) and potential risks (higher false-positive rates, unnecessary biopsies) 2

Women Aged 50-74

• Screening should continue with:
  • Annual screening for ages 50-54
  • Transition to biennial (every 2 years) screening at age 55 1
• This age group shows the most consistent mortality benefit across studies, with a 24% mortality reduction associated with screening 3

Women Aged 75+

• Screening decisions should be based on health status and life expectancy
• Continue screening as long as life expectancy is at least 10 years 1
• Discontinue screening when life expectancy is less than 10 years 1

High-Risk Women

• Women with family history of breast cancer should begin screening 10 years before the youngest age at diagnosis in the family (but not before age 30) 1
• Women with known BRCA mutations or ≥20-25% lifetime risk should receive:
  • Annual mammography
  • Annual MRI 1
• Black women and women of Ashkenazi Jewish heritage should undergo risk assessment by age 25 1
• Risk assessment should consider:
  • Family history of breast cancer
  • Previous breast biopsy showing atypical hyperplasia
  • First childbirth after age 30 1

Supplemental Screening

• Women with dense breasts should consider additional screening with:
  • MRI (preferred method)
  • Contrast-enhanced mammography or ultrasound if MRI is not available 1
• Digital breast tomosynthesis (DBT) is preferred over standard digital mammography for all women 1

Clinical Breast Examination and Self-Examination

• Clinical breast examination is not recommended for average-risk women 1
• Breast self-examination is not recommended due to lack of evidence of benefit and risk of false positives 1
• Instead, breast self-awareness (understanding normal appearance and feel) is encouraged 1

Screening Program in BC

The Screening Mammography Program of British Columbia (SMPBC) has been operating since 1988 and has shown positive outcomes, including:

• Detection of 3,304 cancers from 895,849 screening mammographies 4
• Higher cancer detection rates on first screens (5.0 per 1000) compared to subsequent screens (2.8 per 1000) 4
• 81% of detected invasive cancers had no axillary lymph node metastases 4
• Median size of invasive cancers was 14 mm, indicating early detection 4

Common Pitfalls to Avoid

• Failing to conduct risk assessment by age 25 for high-risk women 1
• Continuing screening in women with life expectancy less than 10 years 1
• Relying solely on mammography for high-risk women or those with dense breasts 1
• Having false reassurance from negative results, as interval cancers can still occur 1
• Not recognizing that non-Hispanic black women, Hispanic black, and Hispanic white women have higher breast cancer mortality and often present at younger ages with more aggressive tumor types 1

Differences Between Guidelines

While this guidance follows the most recent evidence, it's important to note that different organizations have varying recommendations:

• The Canadian Task Force on Preventive Health Care recommends biennial screening for ages 50-69 and does not recommend routine screening for ages 40-49 1, 2
• The American College of Radiology recommends annual screening starting at age 40 1
• The USPSTF recommends biennial screening for ages 50-74 and individualized decisions for ages 40-49 1

The BC approach balances these perspectives with emphasis on mortality reduction while considering individual risk factors.