Expert Insight

Bob Steele, SCPN Co-director, Professor of Surgery at the University of Dundee and chair of the UK National Screening Committee

The UK National Screening Committee (UK NSC) advises ministers and the NHS in the four UK countries about all aspects of screening and supports implementation of screening programmes. In 2016, Prof Bob Steele (Director of Centre for Research into Cancer Prevention and Screening, University of Dundee) was appointed independent chair of this committee. We asked him a few questions about topical issues in cancer screening.

Many men are offered prostate specific antigen (PSA) testing by their GP to test for prostate cancer – how near are we to having a national prostate screening programme?

 
The UK NSC reviewed the evidence for screening men for prostate cancer last year at its November meeting. Whilst it found that the evidence suggests that prostate screening does reduce prostate cancer deaths, the Committee’s overall recommendation was that population screening for prostate cancer should not be offered at this time.

 
This is because:

• The test which is available for use in screening, Prostate-Specific Antigen (PSA), is neither very specific nor very sensitive, and is unable to distinguish between slow-growing and fast-growing cancers.
• There is therefore a risk that a national screening campaign would lead to a high number of false positives.
• There are major harms to treating men who incorrectly test positive. These include impotence, incontinence and rectal problems.
• There is currently no viable alternative test to the PSA, although evaluation is currently taking place which could have the potential to improve the accuracy of PSA testing to identify men at greater risk of fast-growing prostate cancers.
• Thus, the Committee felt that the risk of administering unnecessary and harmful treatments in the case of false positives outweighed the potential reduction in prostate cancer deaths.

The Committee continues to monitor the findings from large trials (the PROTECT study most recently) to see if improvements in tests and treatments will shift the balance of harms and benefit of PSA testing in favour of screening.

 
In the meantime, the National Institute for Health and Care Excellence (NICE) guidelines for Suspected cancer: recognition and referral (June 2015) is available to help GPs assess when it is appropriate to refer patients for suspected cancer, including prostate cancer. The guidelines are available on NICE’s website at www.nice.org.uk/guidance/ng12.

The most recent statistics show that around 600 women in Scotland are diagnosed with ovarian cancer per year. Is there an easy way this can be detected early through screening?

 
Yes, a combination of the circulating tumour marker CA125 (a blood test) and an ultrasound does appear to detect ovarian cancer early. However, the UK Collaborative Trial of Ovarian Cancer Screening has yet to demonstrate that this will prevent deaths from ovarian cancer if it were used in a national screening programme. The UK NSC will wait for further data before a review of the recommendation can be made.

Is there a concern that current lung cancer screening trials might result in a “health certificate” effect for people who smoke but do not have a positive diagnosis?

 
Yes, this is a concern, and it is important that “quit rates” are analysed in the ongoing trials of lung cancer screening.

Sometimes we forget how great the NHS is in offering free bowel cancer screening. People with positive tests are offered a free colonoscopy – how much might this cost in the private sector?

 
Costs in the NHS and in the private sector are not strictly comparable and charges for private procedures are highly variable, but a rough estimate would put the cost of a colonoscopy
at around £1800.