M62 Coloproctology Course

John Northover returned to deliver a keynote lecture on multidisciplinary pelvic surgery. Updates on polyp management, oncology and IBD were among the sessions.

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HNPCC - How Are We Doing?

Jim Hill, Manchester Royal Infirmary

Colorectal Surgeon

Wilson and Jungner criteria for screening
Current UK criteria


The condition

  • The condition should be an important health problem
  • 2-5 % of all colorectal cancer in the UK.
  • The epidemiology and natural history of the condition, including development from latent to declared disease, should be adequately understood and there should be a detectable risk factor, disease marker, latent period or early symptomatic stage.
    • Nearly all carcinomas develop from adenomatous polyps. Most early cancers in HNPCC show residual adenoma (Jass 1995). have In patients with HNPCC there can be more rapid transition from benign to malignant polyps such that the screening interval in individuals with known mutations should be not greater than 2 years. Holland - In individuals on a screening programmes the 10 year cumulative risk of developing colorectal cancer was 10.5% and cancers were found at a lower stage is surveillance intervals were two years or below.
  • All the cost-effective primary prevention interventions should have been implemented as far as practicable.
    • Results of CAPP study awaited (effects of dietary starch and aspirin on polyp formation). Geneticists advice on dietary intake.
  • If the carriers of a mutation are identified as a result of screening the natural history of people with this status should be understood, including the psychological implications.
    • Cumulative lifetime risk to 70y for all mutations combined is 50%. Males have a significantly higher cumulative lifetime incidence of CRC than females. Nearly all screened individuals believe that screening is beneficial and important and screening does not increase psychological morbidity. There is evidence of anxiety prior to screening, which returns to normal levels after screening has commenced.

The test

  • There should be a simple, safe, precise and validated screening test.
    • Colonoscopy meets these criteria. Possibility for stool analysis to be used in the future
  • The distribution of test values in the target population should be known and a suitable cut-off level defined and agreed.
    • Amsterdam criteria well established and used. If satisfied – some units go straight to genetic testing. Bethesda criteria not in universal use. General agreement that immunohistochemistry for the absence of mismatch repair proteins is the most useful first biomarker test. This is not yet established in clinical practice. Testing tumour blocks for microsatelite instability also not established in clinical practice, will likely be used for equivocal immunohistochemistry results.
  • The test should be acceptable to the population.
    • Compliance rates are good for those patients who request assessment of their family history, there are imbalances in the screening population with significantly fewer men and ethnic minorities attending for screening.
  • There should be an agreed policy on the further diagnostic investigation of individuals with a positive test result and on the choices available to those individuals.
    • Screening policy agreed for individuals with HNPCC, generally agreed for those with a significant family history but not meeting the criteria for a diagnosis of HNPCC Gut. 2002 Oct;51 Suppl 5:V1-2.
  • If the test is for mutations the criteria used to select the subset of mutations to be covered by screening, if all possible mutations are not being tested, should be clearly set out.
    • Currently mutation testing for MLH1, MSH2, HSH6 genes (List of pathogenic mutations kept by International Society for Gastrointestinal Hereditary Tumours)

The treatment

  • There should be an effective treatment or intervention for patients identified through early detection, with evidence of early treatment leading to better outcomes than late treatment. There should be agreed evidence based policies covering which individuals should be offered treatment and the appropriate treatment to be offered.
    • Evidence from a screening programme in Finland demonstrated a 62% reduction in CRC and a 65% reduction in overall mortality (3 yearly screening).
  • Clinical management of the condition and patient outcomes should be optimised in all health care providers prior to participation in a screening programme.
    • Management of CRC and benign adenomas is well established

The screening programme

  • There should be evidence from high quality Randomised Controlled Trials that the screening programme is effective in reducing mortality or morbidity. Where screening is aimed solely at providing information to allow the person being screened to make an informed choice, there must be evidence from high quality trials that the test accurately measures risk. The information that is provided about the test and its outcome must be of value and readily understood by the individual being screened.
    • No randomised controlled trial data
  • There should be evidence that the complete screening programme (test, diagnostic procedures, treatment/ intervention) is clinically, socially and ethically acceptable to health professionals and the public.
  • The benefit from the screening programme should outweigh the physical and psychological harm (caused by the test, diagnostic procedures and treatment).
  • The opportunity cost of the screening programme (including testing, diagnosis and treatment, administration, training and quality assurance) should be economically balanced in relation to expenditure on medical care as a whole (ie. value for money).
    • No formal assessment of this
  • There should be a plan for managing and monitoring the screening programme and an agreed set of quality assurance standards.
    • In place for National Screening Programme for sporadic cancer – not for HNPCC
  • Adequate staffing and facilities for testing, diagnosis, treatment and programme management should be available prior to the commencement of the screening programme.
  • Most units can cope with the relatively small demand
  • All other options for managing the condition should have been considered (e.g. improving treatment, providing other services), to ensure that no more cost effective intervention could be introduced or current interventions increased within the resources available.
  • Evidence-based information, explaining the consequences of testing, investigation and treatment, should be made available to potential participants to assist them in making an informed choice.
    • Can only really be done by genetics departments. No information regarding the proportion of patients entered into screening programmes via genetics departments is available.

Limitations of screening

  • Screening can reduce the risk of developing a condition or its complications but it cannot offer a guarantee of protection.
  • In any screening programme, there is an irreducible minimum of false positive and false negative results.
  • Screening is therefore increasingly presented as risk reduction.
Potential dangers of screening 
Although screening programmes may benefit populations, not all participants will benefit and some will even be harmed by participation.
  • Personal costs include problems with false positive results, which can lead to distress and possible unnecessary treatment.
  • Even individuals who choose not to participate in screening may be disadvantaged, for example being labelled as from a "positive family" with regard to genetic susceptibility, when other family members have chosen to be screened and found positive..
  • False negatives also can occur, as no test is 100% sensitive, which can then lead to false reassurance by both patients and doctors. This may even dissuade patients from returning for future screening tests.
  • Misinterpretation of results can lead to a false sense of security, e.g. patients with normal cholesterol or normal blood pressure may continue to smoke.
  • Costs to society: actual costs of equipment, services, treatment etc and also the time taken off work for people to attend for the screening test and the treatment.
  • Psychological costs involved. One article showed that false positive results in screening tests can have undesirable effects.4 Women who had been given the "all clear" after having had abnormal mammography results three years previously remained significantly more anxious than those who had normal results. This was actually sufficient to deter 15% of them from attending for mammography at all the next time round.
  • Prophylactic mastectomy although perhaps an effective intervention in BRCA mutation, requires evidence on psychological and social impact.
  • Some people have different health beliefs and cultures and object to being screened. This needs to be appreciated when considering individual autonomy.
  • Implementing screening tests may mean that funds are diverted away from other services, e.g. cancer treatments.

Document References

  • UK National Screening Committee; Definition of screening.
  • JMG Wilson and G Jungner in Principles and Practice of Screening for Disease, WHO 1968.
  • Brett J, Austoker J; Women who are recalled for further investigation for breast screening: psychological consequences 3 years after recall and factors affecting re-attendance. J Public Health Med. 2001 Dec;23(4):292-300. [abstract]
  • Marteau TM, Kinmonth AL; Screening for cardiovascular risk: public health imperative or matter for individual informed choice? BMJ. 2002 Jul 13;325(7355):78-80.
  1. Knowledge of disease:
    1. The condition should be important
    2. There must be a recognisable latent or early symptomatic stage –Natural course of condition, including development from latent to declared disease, should be adequately understood –
  2. Knowledge of test:
    1. Suitable test or examination – colonoscopy completion and complication rates are known and
    2. Test acceptable to population –Case finding should be continuous (not just a "once and for all" project). It is essential that screening programmes have accurate and validated recall systems for their screening programmes.
  3. Treatment for disease:
    1. Accepted treatment for patients with recognised disease
    2. Facilities for diagnosis and treatment available
    3. Agreed policy concerning whom to treat as patients -
  4. Cost considerations:
Costs of case finding (including diagnosis and treatment of patients diagnosed) economically balanced in relation to possible expenditures on medical care as whole.

To register fill in the registration form and send it off complete with a cheque to pay for your course.

Course Fee: £240

Mr J Hartley
Consultant Surgeon
Academic Surgical Unit
Castle Hill Hospital
Cottingham
East Yorkshire
HU16 5JQ

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