Chapter 1: Screening, diagnosis & staging of breast cancer and multidisciplinary team working
Breast cancer screening (continued)
In general, screening-detected BCs are associated with a favourable prognosis.
Prognosis of screening-detected cancers is favourable even when compared with non-screening-detected cancers of a similar size.
Figure 1.19: Interval cancer detection.
Credit: courtesy of the authors.
Interval cancers that are detected between the screening rounds tend to have a less favourable prognosis compared with screening-detected cancers.
The benefits of BC screening need to be balanced with its potential harms. Screening is associated with a small radiation hazard.
Figure 1.20: US-guided breast biopsy.
Abbreviations: US, ultrasound.
Credit: courtesy of the authors.
False-positive findings may lead to re-imaging and a breast biopsy. Some screening-detected ductal in situ carcinomas and small cancers (about 10%) are over-diagnosed, unlikely to threaten life, leading to overtreatment.
Screening carries a risk for false-negative findings (about 20%), which may lead to unsubstantiated feeling of security and cancer detection as interval cancer.
Annual screening with MRI of the breast and US or mammography is recommended for women with a high familial BC risk, when risk-reducing mastectomy is not the preferred option.
When the familial risk is high, intensified screening including MRI detects BC earlier compared with mammography screening alone.
Figure 1.21: A pedigree suggesting a high hereditary BC risk.
Abbreviations: BC, breast cancer.
Credit: courtesy of the authors.
When a germline pathogenic variant of BRCA1, BRCA2 or PALB2 is present, intensified screening should start at age 30, or 5 years younger than the age at which the youngest relative was diagnosed with BC.
Revision questions
- Is the prognosis of interval cancers comparable to that of screening-detected cancers?
- What are the potential harms associated with mammography screening?
- What imaging modalities should be used when familial BC risk is high?
