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Questions

  1. What event prompted the practice to become interested in screening?
    • Family of a CRC patient asked whether it may have been prevented earlier
  2. What are the risk factors for colorectal cancer?
    • Age
    • IBD
    • Low vitamin D
    • Polyps
    • Male gender
    • Obesity
    • Poor diet (high fat, low diet)
    • Family history
    • T2DM
    • Smoking
    • Alcohol
    • Sedentary lifestyle
    • Radiation therapy for cancer
    • Inherited syndromes (FAP, Lynch syndrome)
    • Personal history
    • African American race
    • Coeliac's disease
  3. Why did the registrar ignore Paul’s FOBT result? What problems does this illustrate about the FOBT test? What are other possible issues with the FOBT test?
    • Previous experience of bowel perforation
    • Patient didn't adhere to no-meat diet
    • Should have been re-tested
  4. What aspects of the screening criteria did the practice consider when deciding to implement screening?
    • Looked at the cost/benefit analysis
    • The registrar found that cancer is an important health problem in Australia because it is common and causes a high number of deaths (Appendix 2). The registrar found evidence to support FOBT. It seemed to meet the WHO criteria for screening (Appendix 3). Screening was shown in a recent Cochrane Review to reduce the relative risk of colorectal cancer mortality by 16%. He found that in screening low risk people over the age 50 with FOBT, about 9% would have a positive result. Of these, 15% would have an adenoma and 5% colon cancer. The sensitivity is about 33% and specificity 92%. Colonoscopy costs about $1,000 and has a complication rate of about 1 in 1,000. A cost effectiveness study conducted in Australia has estimated that FOBT screening costs around $17,000 per DALY averted, which compares well to sigmoidoscopy ($12,000 to $40,000) and colonoscopy ($9,000 to $22,000).
    • Risk factors of disease
    • The practice then considered how they would identify those at risk. They decided on two groups of patients:
      • Over the age of 50 without family history
      • Patients aged 40-50 with a family history
  5. How did the practice identify patients in high risk groups? Do you agree with what they did? If not, how would you do it?
    • Logistically difficult - records in a GP are often not complete. It is difficult to get family history
  6. What was the response rate to the recall letters?
    • 48%
    • low income, indigenous patients and migrants were less likely to present for screening (only 20%, 15% and 18% respectively)
    • Overall, 13 test results (or 9%) were positive. 11 patients came back for follow up, but 2did not.
  7. How did they try to improve the response rate?
    • The receptionist at the practice made phone calls to the 2 patients and 1 more patient returned for follow up, but 1 patient never returned.
    • The practice considered how to raise awareness of the issue in the community. With assistance from the Medicare Local and small funding from a local service club, they ran a media campaign to promote colorectal cancer screening in the local print and radio.
  8. How effective was this and why? What else could they have done?
    • After the campaign, the overall response rate increased by 32 (i.e. a total of 176) but no additional low income, migrant or indigenous patients presented. (SOCIAL GRADIENT)
  9. How many people with a positive FOBT result did not return for follow up? Why do you think this happened? What are the implications of this and how would you address this issue?
    • Overall, 13 test results (or 9%) were positive. 11 patients came back for follow up, but 2did not. The receptionist at the practice made phone calls to the 2 patients and 1 more patient returned for follow up, but 1 patient never returned.
    • Low health literacy, low SES (can't afford appointment)
  10. If 1,000 people were screened by FOBT, how many would have pathology found at colonoscopy? How many would have false positives and false negatives? (Use figures supplied)
    • TP = 18
    • TN = 873
    • FP = 73
    • FN = 36
  11. What problems were experienced at the local hospital?
    • Waiting times increase
    • CEO of hospital copped flak
    • Hospital criticised the GP
    • Coordinated effort required
    • The GP should have informed the hospital that they're starting a screening program and that they may need to reallocate resources for colonoscopies etc
  12. What do you think about analysing the effectiveness of a screening program by looking at all-cause mortality rate?
      • People who are aware of screening and respond to invitations are more likely to respond to other screening/healthcare interventions as well
    • Inverse care law: people who need care the most don't receive as much as people who need less care
    • So we're selecting for a healthy population -- FOBT-compliant are more likely to be healthy in other ways
      • Also affects probability of follow up
    • Bowel cancer markers: CEA
      • Not cost effective
      • Tumour markers circulate at a non-treatable stage of the disease (late-stage disease)
  13. What are some of the problems with a nation-wide screening program? How might you address these issues?
    • Cost-benefit analysis
    • Rollout, organising clinics to undertake the screening programme
    • Legal issues
    • Loss of efficacy due to poor follow up
    • Social gradients produced by health literacy differences
    • Get public health authorities to devise a programme that won't result in system overload (particularly in the hospital where colonoscopies need to be done)
    • Educational materials (regarding screening etc) need to be made available in different languages

National bowel cancer screening program

To complicate matters further, some of the registrar’s patients mentioned to him that they had received an invitation letter from the National Bowel Cancer Screening Program. When the registrar raised this issue at their next teaching session, Dr Andrews told him that this was a program that involved a one-off series of FOBT tests when the patient turned 50, 55, 60 or 65 years of age - with plans to extend the program to patients turning 70 from 2015 and to a biennial screening program from 2017/8 (Appendix 6). The registrar then asked Dr Andrews what role do the GPs and the practice have in the screening program and what duty of care is owed to the patient with an abnormal result (Appendix 7). He also wondered whether the National Bowel Cancer Screening Program had been effective and whether they might experience similar problems that the practice had with their screening program in not getting enough patients from certain socioeconomic, cultural and indigenous background to participate (Appendix 8 and 9).

  • Literature suggests 2 yearly from age 50 is required. This won't happen in Australia until 2017/18 - a lot of cancers between now and then
    • What can we afford? What happens to the follow-up (colonoscopy - can we afford it and do we have enough surgeons, and can we treat them?)
  • Also remember that not all patients with bowel cancer have risk factors

Mistakes the registrar made

  • Uses anecdotal evidence rather than statistics
  • He didn't ask his colleagues - just operated on emotional/anecdotal experience rather than asking a colleague
  • Once you have a single FOBT, you need to follow it up (you're duty bound to do it)
    • Once you're getting a positive FOBT on each poo, it's quite advanced cancer


Screening data

Pos Dis Neg Dis
Pos Test 18 73 91
Neg Test 36 873 909
54 946 1000
  • Specificity = 0.92
  • Sensitivity = 0.33
  • PPV = 0.2
  • Therefore people are suggesting that we should have colonoscopy as our new method for screening
    • Also sigmoidoscope
  • FN causes false reassurance

Cost of colonoscopy + FOBT

  • FOBT is $35, colonoscopy is $1000 with a day off
  • Access - rural areas, they have to travel to the city for the day to get access to the procedure
  • Language barrier
  • Sigmoidoscopy better than FOBT but not as good as colonoscopy
  • Other barriers include side-effects of prep, and time of prep + procedure

Screening criteria

Receiver operating curve
  • The condition
    • should be an important health problem (either common or rare+serious)
    • should have a recognisable latent or early symptomatic stage
    • the natural history of the condition, including development from latent to declared disease, should be adequately understood
  • The test
    • should be simple, safe, precise and validated
    • should be acceptable to the target population
    • the distribution of test values in the target population should be known and a suitable cut-off level defined and agreed
    • receiver operating curve
  • Treatment
    • there should be an effective treatment for patients identified, with evidence that early treatment leads to better outcomes
    • there should be an agreed policy on who should be treated and how
    • facilities for diagnosis and treatment should be available
  • Outcome
    • there should be evidence of improved mortality, morbidity or quality of life as a result of screening and that the benefits of screening outweigh any harm
    • the cost of case finding (including diagnosis and treatment of patients diagnosed) should be economically balanced in relation to possible expenditure on medical care as a whole
      • cost benefit analysis
  • Consumers
    • Should be informed of the evidence so that they can make an informed choice about participation

Informed consent

  1. Informed
  2. Voluntary
  3. Truthful

Patient requesting colonoscopy without risk factors

  • Informed consent -- tell them risk of procedure vs their risk of bowel cancer
  • Refer them for a second opinion
  • Document everything - if you say no and they have cancer you get sued.
  • Second opinion, second opinion, second opinion

Deal with cancer patient

  • Provide them hope as it's not a hopeless case
  • There is no benefit to the patient now in going through how it might have been prevented in the past
  • Better off saying - we'll send you to the best specialist, optimise your lifestyle factors, and try to make you part of the 30% that survive.
  • Be positive and constructive
    • There are risk factors, that isn't a guarantee that you won't get cancer!
    • Don't blame the patient
  • Secondary prevention
    • Get weight under control
    • Followup colonoscopies
    • Referral to dietician
    • Look at family history down the line
    • SNAP: smoking, nutrition, alcohol, physical activity
    • Get out in the sun
  • Deal with them as though you see they have a future - they can tell
    • Put the patient in control
  • Need to screen the children in future
    • Surveillance colonoscopies