Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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![[Read Rapid Response]](/icons/misc/sectionDOWN.gif)
Appropriateness of 5 year survival statistic
- Brian R. Jackson (31 March 2006)
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Understanding false negative FOB results
- David A Gorard (1 April 2006)
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be positive
- Nikola A Henderson (6 April 2006)
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Delay disappointing but presents opportunities
- Ros Jervis, Gurmukh S. Kalsi, Consultant in Public Health (6 April 2006)
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Informed consent for screening
- John Doherty (6 April 2006)
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The Importance of 'Pooh-Sticks'
- Marcia A Ratcliffe (9 April 2006)
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Brian R. Jackson, Pathologist ARUP Laboratories, Salt Lake City, UT, USA, 84108
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To the Editor: I'm surprised to see BMJ, a leader in promoting statistical literacy, publish an editorial with such an obvious misuse of a statistic. 5-year survival is of no value in assessing the effectiveness of a cancer screening program. Any screening program will improve 5-year survival simply by detecting cancers earlier, thereby starting the 5-year clock earlier, whether or not there is any true mortality benefit to the program. This will be true even in the absence of effective therapy, or of any therapy at all. Likewise, it is not surprising that stage of disease at diagnosis would be the main determinant of 5-year survival, but again this tells us nothing about the value of the screening program. What is relevant is the effect of the program on overall mortality. --Brian Jackson Competing interests: None declared |
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David A Gorard, Consultant Gastroenterologist Wycombe Hospital, Bucks, HP11 2TT
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A large administrative, financial and manpower input is needed to realise the small but definite gains to be obtained from colon cancer screening using guaiac-based faecal occult blood (FOB) testing (1). Since a 16% reduction in colorectal cancer deaths is achievable, 84% of colorectal cancer deaths are not prevented by such a screening programme. To date there has been little focus on the perception of false results by screened individuals. For every 10 individuals who screen FOB positive, one may have bowel cancer, 4 may have adenomatous polyps of various sizes and 5 will have a false positive result. Professor Atkin emphasises that prompt colonoscopy is needed for positive FOB individuals in order to allay anxieties (1). False negative results are perhaps more concerning. While a negative screening test result might be expected to be reassuring, many patients who are FOB negative will nevertheless be harbouring a colon cancer. FOB fails to detect 25-50% of colon cancers and up to 75% polyps. Interval cancers after negative FOB results were common in the Nottingham study (2). Since doctors themselves are often falsely reassured by negative FOB results in individual patients, how can members of the public be educated about the concept of a false negative result? Misunderstandings about false negative results in cervical and breast cancer screening programmes have often led to furore and unwelcome media and legal attention (3). In colon cancer screening this issue is going to be on a greater scale, and potential screenees must be advised that a negative FOB result is not a guarantee that they do not have colon cancer. References 1. Atkin WS. Impending or pending? The national bowel cancer screening programme. BMJ 2006; 332:742. 2. Hardcastle JD, Chamberlain JO, Robinson MHE et al. Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet 1996; 348: 1472-77. 3. Wilson RM. Screening for breast and cervical cancer as a common cause of litigation. BMJ 2000; 320:1352-3. Competing interests: None declared |
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Nikola A Henderson, Research Fellow Deaprtment of Surgery & Molecular Oncology, University of Dundee, Ninewells Hospital, Dundee, DD19SY
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As a trainee in general surgery in Scotland with an interest in colorectal surgery, the advent of our national screening programme next March is one that I greet with considerable enthusiasm; it is an exciting time to be involved in colorectal cancer care and no doubt we will be presented with the opportunity to answer a great many questions in the treatment, prevention and molecular genetics of adenomas and adenocarcinomas of the colon and rectum. The FOB is a crude and simple test but has proved itself worthy of use as evidenced by the mortality reductions convincingly shown by the Minnesota study in 1993 (1) and also by Hardcastle (2) and Kronborg (3) in 1996. As a profession we must embrace this screening programme and instead of focusing on the negatives, be they either the considerable number of false negatives or negative opinions about colorectal cancer screening and instead turn our focus onto maintaing pressure on the government. There is no doubt that we need to continue to actively search for either a better stool or serum biomarker or a better investigation but we cannot let another ten years pass us by before we force the politicians to fund this programme. 1. Mandel, J.S. et al. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med 328, 1365-71 (1993). 2. Hardcastle, J.D. et al. Randomised controlled trial of faecal-occult- blood screening for colorectal cancer. Lancet 348, 1472-7 (1996). 3. Kronborg, O., Fenger, C., Olsen, J., Jorgensen, O.D. & Sondergaard, O. Randomised study of screening for colorectal cancer with faecal-occult- blood test. Lancet 348, 1467-71 (1996). Competing interests: None declared |
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Ros Jervis, Specialist Trainee in Public Health Wolverhampton City Primary Care Trust, Coniston House, Chapel Ash, Wolverhampton, WV3 0XE., Gurmukh S. Kalsi, Consultant in Public Health
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EDITOR - The editorial by Professor Atkin is right to emphasise the case for population bowel cancer screening.1 Bowel cancer is an important public health problem and a common cause of cancer related death. The major determinant of survival is disease stage. Early presentation (Dukes’ Stage A) can result in up to 83% five year survival.2 The most effective way of improving survival outcomes for bowel cancer is early diagnosis. Primary care plays a pivotal role in encouraging earlier presentation by patients with bowel symptoms, compliance with ‘Urgent Referral’ criteria2 and primary prevention. However the fact is that the present financial crisis in the NHS has resulted in a delay in the commencement of the national bowel cancer screening programme. This is disappointing news both nationally and locally. In the meantime, this presents a further opportunity for local health services to develop and/or refine their implementation plans for the roll out of the screening programme. In Wolverhampton, the Primary Care Trust’s Public Health Department has developed an initial implementation plan in conjunction with the Local Screening Centre (LSC), primary care and potential screening participants. A discussion of the impending NHS Bowel Cancer Screening Programme (NHS BCSP) at a recent Wolverhampton Over 50’s Forum raised some important issues. First, the acceptability of the faecal occult blood test (FOBt) to individuals was mixed. Men in particular expressed concern about using the testing kit. Individuals with common pre-existing bowel conditions, such as irritable bowel syndrome, wanted to know whether or not they should participate in screening. Concerns were also expressed regarding the risks associated with colonoscopy. Encouragingly however, the main focus of discussion related to preventative measures that could be taken, such as dietary control, physical activity, weight management and a reduction in both tobacco use and alcohol consumption. The UK Screening Pilots3 show several factors that affect FOBt uptake rates, including deprivation and ethnicity. These factors are of particular concern in Wolverhampton. For example, the city is host to the fourth biggest Sikh community in the country.4 This intervening period presents us with a further opportunity to raise awareness of bowel cancer with disparate groups through existing primary care and local authority networks and communication channels. New ways of presenting health promoting and bowel cancer screening material are being explored, such as through the local Asian media and faith organisations. Our local general practitioners (GPs) also believe that the new programme will have an impact on their workload. Resources can be directed towards establishing helplines for both professionals and the general public in order to provide appropriate advice and information on the screening programme. Locally, education events aimed at GPs and other health professionals will continue as planned. The government has confirmed that it is committed to a national bowel cancer screening programme.5 This period of delay can be used to continue work that will not only maintain existing improvements in bowel cancer survival rates but also create an environment that will assist the implementation of the national screening programme, when this ultimately takes place. Ros Jervis, Specialist Trainee in Public Health, Wolverhampton City Primary Care Trust Dr Gurmukh Singh Kalsi, Consultant in Public Health, Wolverhampton City Primary CareTrust References 1. Atkin W. S. Impending or pending? The national bowel cancer screening programme. BMJ 2006; 332:742. 2. NICE. Guidance on Cancer services – Improving Outcomes in Colorectal Cancers. Manual Update. May 2004. ISBN 1-84257-620-8. 3. The UK CRC Screening Pilot Evaluation Team. Evaluation of the UK Colorectal Cancer Screening Pilot – Final Report. May 2003. University of Edinburgh. 4. Wolverhampton Public Health. Annual Report 2005. Wolverhampton City Primary Care Trust 5. Winterton R. Hansard. House of Commons Daily Debates. 27 March 2006: Column 780W. Available at: http://www.publications.parliament.uk/pa/cm200506/cmhansrd/cm060327/text/60327w40.htm#60327w40.html_sbhd2 Competing interests: None declared |
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John Doherty, Medical Director IAEA, Vienna, Austria 1400
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Atkin bemoans the delay in starting the national bowel cancer screening programme [1], but the additional time could be devoted to giving the public balanced information on the likely harms and benefits. If this were done by a disinterested party it would avoid the conflict of interest seen in breast cancer screening [2]. Extra time may, indeed, be necessary to explain why 109 more people died in the screening group than in the control group during the trial she cites (the largest so far undertaken)[3]. 1. Atkin WS. Impending or pending? The national bowel cancer screening programme. BMJ 2006; 332:742. 2 Jørgensen KJ, Gøtzsche PC, Content of invitations for publicly funded screening mammography. BMJ 2006;332: 538-41. 3 Hardcastle J, Chamberlain J, Robinson M, Moss S, Amar S, Balfour T, et al. Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet 1996;348:1472-7. Competing interests: None declared |
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Marcia A Ratcliffe, associate specialist in haematology and oncology department of haematology, ward 16, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, AB25 2ZN
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EDITOR- Following Professor Atkins’ editorial I’m writing to add my concerns at the delay in introducing the national bowel screening programme.1 I have been very fortunate in living in the North East of Scotland which has had a pilot bowel screening programme for those aged 50 to 69 years for over 5 years now. At aged 52, almost two years ago, my small asymptomatic but Dukes C colonic carcinoma was picked up as a result of screening. After six months of adjuvant chemotherapy I am well with now, an excellent prognosis. I would not be but for my address and I’m sure there are patients in the west midlands who feel the same. I have encouraged all my family in non screening areas to have screening guaiac FOB (faecal occult blood) tests through their GP’s which they have done. Two have required further investigation with colonoscopy. The 60% take up of screening is disappointing with the extremely high incidence of bowel cancer. As an associate specialist in oncology and haematology I carried out a straw poll amongst my colleagues on their take up of the screening programme. It was also no higher than 60%. This was due to a combination of “knowing” that any positive FOB would be the result of bleeding haemorrhoids and a certain reluctance to have GI colleagues know them any better than they did already! However, after my experience, and with the tragic consequences of a close friend in the department who declined screening, take up of screening in the unit has improved significantly this year. The national bowel cancer screening programme is extremely important and must not be delayed. The plans to initially exclude the 50 to 60 year group I cannot accept. With the increasing cost of chemotherapy and monoclonal antibody regimens for advanced colonic carcinoma the government must surely realise the financial benefit of preventative screening. 1 Atkin W S. Impending or pending? The national bowel cancer screening programme. BMJ 2006;332:742 Competing interests: None declared |
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