PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Breast cancer is the most common cancer in the UK, with women having a 1 in 8 lifetime risk of developing the disease. Many trials have looked at whether screening has an impact on outcome in terms of mortality and morbidity. Several countries have set up screening programmes to call women for routine screening. Debate over the benefit, however, continues.
The programme in the UK was initiated in 1988 following the Forrest Report. There are 80 breast screening centres across England, 6 in Scotland, 10 in Wales and 4 in Northern Ireland, many providing mobile units to provide local appointments.
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Screening for breast cancer: benefit vs harm
The breast cancer screening programme in the UK was set up to allow for the early detection and treatment of breast cancer in women. As evidence emerges from years of screening across several countries, debate continues about whether the benefit outweighs the negative effects.
- An independent review in the UK in 2012 concluded:
- Screening as currently performed in the UK gives a 20% relative risk reduction in mortality.
- For every 10,000 women aged 50 beginning the screening programme for the next 20 years, 43 deaths from breast cancer would be prevented, and 129 cases would be overdiagnosed. This equates to one death prevented for every three cases overdiagnosed.
- A 2013 Cochrane review concluded:
- Screening reduces mortality by around 15%, and overdiagnosis and overtreatment is around 30%.
- For every 2,000 women invited for screening over 10 years, one will avoid dying of breast cancer, and 10 healthy women will be treated unnecessarily. More than 200 women will experience psychological distress caused by false positive findings.
- Breast cancer mortality in itself is an unreliable outcome measure, as it is biased in favour of screening.
- The Canadian Task Force in 2011 found that mammography is associated with significant reductions in the relative risk of death from breast cancer in those aged 50-69 years. The benefits of mammography for women aged 60-69 years (number needed to screen (NNS) 432) are greater than for women aged 50-59 years (NNS 910). Screening about 720 women aged 50-69 years once every 2-3 years for about 11 years would prevent one death from breast cancer, but it would also result in about 204 women having a false positive result on a mammogram and 26 women having an unnecessary biopsy of their breast.However, a report on 25 years of breast screening in Canada in 2014 suggested for women aged 40-59 years having annual mammography, there was NO significant reduction in mortality.
- For women aged 40-49 years there is only limited evidence of a reduction in mortality. This may be due to the difficulties in interpreting mammograms in premenopausal women, due to glandular breast tissue, and also to the lower incidence of breast cancer in this age group.
- There is some evidence to suggest that reduction in mortality is independent of screening practice.
- Some analyses suggest there may be evidence to support an overall net harm for women screened.
- There is evidence that women in the UK who have had false positive breast screening results may experience psychological distress which may persist for up to three years, and reduce their likelihood of returning for their next screening test.
- Women need to be informed of the risk of overdiagnosis but a recent small study suggested that this did not have much impact on their decision to have screening.
All women between the ages of 50 and 70 are invited to attend for screening every three years. 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. Women over the target age may request mammography by contacting their local screening centre. The programme is now phasing in an extension of the age range of women eligible for breast screening to those aged 47-73. This started in 2010 and is expected to be complete by 2016.
Uptake and detection rates are similar across England, Scotland, Wales and Northern Ireland, although there are regional variations. In 2011-12 in the group aged 50-70 years:
- In England uptake of invitation for screening was 73.1%. Rate of uptake is lowest in London. 7.8 cases of cancer were detected per 1,000 women screened.
- In Wales uptake was 73.2% (71.2% in 2012-13). 10.2 cancers were detected per 1,000 women screened.
- In Scotland uptake was 74.5% (over the 2009-12 three-year period).
- In Northern Ireland average uptake was 73.8%, although regional variation was noted. 7.2 cancers were detected per 1,000 women screened.
Women who have a family history of breast cancer can access advice about their risks and further screening if required, through their GP. National Institute for Health and Care Excellence (NICE) guidelines of 2013 may be consulted for appropriate referral pathways for genetic testing and surveillance for those at higher risk.
Otherwise, primary care clinicians should be aware of women who may be at higher risk of breast cancer - for example, no history of breast-feeding, having no children, having children at late ages (especially over 30), long-term hormone replacement therapy (HRT) use, obesity (for postmenopausal women only) and high consumption of alcohol - and advise them opportunistically of breast awareness.
What screening involves
Screening in the UK is a nationally co-ordinated programme, with national standards monitored through a quality assurance network.
Screening takes place in the form of clinical examination and mammography. This allows small tumours to be detected before they are palpable. Since 2003, two images of each breast have been taken, craniocaudial, and mediolateral, and this increases the detection rate of even smaller abnormalities by up to 43%. Most mammography now uses digital images stored on computer.
Around 1 in 23 women having a mammogram are called back; some of these are for technical reasons, but around 4% require further assessment. 42% of these women have either fine-needle aspiration or core biopsy.
Further reading & references
- Quality Assurance Guidelines for Surgeons in Breast Cancer Screening; NHS Cancer Screening Programmes, NHSBSP Publication No 20, Fourth edition (March 2009)
- Primary breast cancer: ESMO Clinical Practice Guidelines for diagnosis treatment and follow-up; European Society for Medical Oncology (Aug 2013)
- Breast cancer incidence (invasive) statistics; Cancer Research UK.
- Forrest APM; Breast Cancer Screening: report to the health ministers for England, Wales, Scotland and Northern Ireland, HMSO, 1986.
- Breast screening across the UK; UK Screening Portal
- The benefits and harms of breast cancer screening: an independent review; Lancet. 2012 Nov 17;380(9855):1778-86. doi: 10.1016/S0140-6736(12)61611-0. Epub 2012 Oct 30.
- Gotzsche PC, Jorgensen KJ; Screening for breast cancer with mammography. Cochrane Database Syst Rev. 2013 Jun 4;6:CD001877. doi: 10.1002/14651858.CD001877.pub5.
- Tonelli M, Gorber SC, Joffres M, et al; Recommendations on screening for breast cancer in average-risk women aged 40-74 CMAJ. 2011 Nov 22;183(17):1991-2001.
- Miller AB, Wall C, Baines CJ, et al; Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial. BMJ. 2014 Feb 11;348:g366. doi: 10.1136/bmj.g366.
- Autier P, Boniol M, Gavin A, et al; Breast cancer mortality in neighbouring European countries with different levels BMJ. 2011 Jul 28;343:d4411. doi: 10.1136/bmj.d4411.
- Raftery J, Chorozoglou M; Possible net harms of breast cancer screening: updated modelling of Forrest BMJ. 2011 Dec 8;343:d7627. doi: 10.1136/bmj.d7627.
- Bond M, Pavey T, Welch K, et al; Systematic review of the psychological consequences of false-positive screening mammograms. Health Technol Assess. 2013 Mar;17(13):1-170, v-vi. doi: 10.3310/hta17130.
- Waller J, Douglas E, Whitaker KL, et al; Women's responses to information about overdiagnosis in the UK breast cancer screening programme: a qualitative study. BMJ Open. 2013 Apr 22;3(4). pii: e002703. doi: 10.1136/bmjopen-2013-002703. Print 2013.
- Familial breast cancer: Classification and care of people at risk of familial breast cancer and management of breast cancer and related risks in people with a family history of breast cancer; NICE Clinical Guideline (June 2013)
- Breast screening; NICE CKS, December 2011 (UK access only)
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Hayley Willacy
Dr Mary Harding
Dr Jacqueline Payne