Breast Screening And DCIS Flashcards
Why do the NHS do breast screening?
Screening prevents death from breast cancer by finding breast cancers at an early stage when they are too small to see or feel.
How prevalent is breast cancer?
• Breast cancer is the most common cancer in the UK, with women having a 1 in 8 lifetime risk of developing the disease.
When was screening initiated in the UK?
• The programme in the UK was initiated in 1988 following the Forrest Report.
Which imaging technique is used in breast screening?
- Mammography is the tool used for breast screening. This allows small tumours to be detected before they are palpable.
- Most mammography now uses digital images stored on computer. A digital mammography system usually requires a lower radiation dose than film screen mammography for the same image quality.
- Digital detector converts the X-ray photons to an electronic signal, which is further processed and displayed as a greyscale image.
What are the benefits of digital mammography?
- The digital system provides greater contrast resolution and thus better visualisation of skin, peripheral breast tissue, and breast density.
- Besides this, it allows for changes in zoom, contrast and brightness, which increase the ability to detect subtle abnormalities.
- Since 2003, two images of each breast have been taken, craniocaudal and mediolateral oblique. This increases the detection rate of even smaller abnormalities by up to 43%.
What is the rates of recalls in breast cancer screening?
- Around 80% of women who are recalled for assessment following an abnormal mammogram do not have breast cancer.
- Around 1-2 in 23 women having a mammogram are called back; some of these are for technical reasons.
Which investigations are doing for recalled women?
• Recall of women with abnormalities is usually to specialised assessment units.
These allow further investigation, with one or more of the following:
o Clinical examination.
o Special view mammography:
It gives a close-up detailed image of a small area of breast tissue, and is used to assess the size, shape and pattern of microcalcification.
o Ultrasound examination (useful in younger patients and to identify cysts particularly).
o Fine-needle aspiration and cytology.
What is the target population for breast cancer screening?
47-73 years.
What is he frequency of breast cancer screening?
3 years
Are women invited for screening as soon as they reach the target age?
• It is a rolling programme, which means that not all women will be invited when they reach 50 years, but all will be invited before their 53rd birthday.
Can women over the target age get screening?
• Women over the target age may request mammography by contacting their local screening centre.
What are the three main reasons to put a woman at high risk of developing breast cancer?
• The three main reasons for a women to be in the high risk category are BRCA gene mutations, tp53 gene mutation and previous supradiaphragmatic radiotherapy.
Women at high risk start screening at an earlier age, undergo annual rather than three-yearly screening and have MR in addition to mammography.
Both modalities are needed as some abnormalities like calcification are better seen on mammography.
What is the benefit of screening for breast cancer?
• Saving lives from breast cancer
o Screening saves about 1 life from breast cancer for every 200 women who are screened. This adds up to about 1,300 lives saved from breast cancer each year in the UK.
What is the harm of screening for breast cancer?
• Finding cancers that would never have caused a woman harm
o About 3 in every 200 women screened every 3 years from the age of 50 to 70 are diagnosed with a cancer that would never have been found without screening and would never have become life-threatening.
o This adds up to about 4,000 women each year in the UK who are offered treatment they did not need.
• Overall, for every 1 woman who has her life saved from breast cancer, about 3 women are diagnosed with a cancer that would never have become life-threatening.
What are the problems with breast cancer screening?
- Mammography is uncomfortable and involves a small amount of radiation
- False-positive results may cause unnecessary anxiety
- Breast screening occasionally misses a cancer
- Breast cancer may occur in the interval between screening appointments
