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MCC 2011 - Slide 18
 

MCC 2011 - Slide 18

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    MCC 2011 - Slide 18 MCC 2011 - Slide 18 Presentation Transcript

    • Screening for colorectal cancer Lars Påhlman Dept Surgery, Colorectal unit University Hospital, Uppsala, Sweden
    • What is screening
    • ‘ The presumptive identification of unrecognised disease or defect by application of tests, examinations or other procedures that can be applied rapidly’ U.S. Commission on Chronic Illness
    • Ideal screening situation
      • Cut - off value
      • No disease Disease
      • - test + test
    • The common screening situation
      • Cut - off value
      • No disease Disease
      • - test + test
    • Colorectal cancer - Screening
      • Screening is not a diagnostic test.
      • A positive test must in most situations be followed by another test.
    • Colorectal cancer - Screening
      • The disease must be difficult to treat once it is symptomatic.
      • There must be advantages with early detection.
      • The test must detect pre -clinical lesions
    • Colorectal cancer - Screening
      • High sensitivity !
      • A negative predictive value is important, i.e., to give a correct answer when the test is negative.
      • High specificity !
      • Important to avoid false positive test , i.e., reduce unnecessary investigations.
    • Colorectal cancer - Screening
      • Screening does not reduce the incidence.
      • Data on survival and stage are difficult to interpret; ( length time bias and lead-time bias ).
      • Mortality the ‘true’ endpoint
      • Risk for selection bias ( randomised trials preferable).
    • A B Detectable by screening Clinically detectable Length biased sampling Time
    • Length time bias
      • X
      • X
      • X
      • X
      • X
      • X
    • Time A B C D The disease starts Detectable Clinically presented Death Lead time Lead time bias
    • Lead time bias
      • X
      • X
      • X
      • X
      • X
      • X
    • Prevention Cure Early diagnosis
    • Colorectal cancer
      • Prevention
      • Changing life style ?
      • No
    • Colorectal cancer
      • Chemo - prevention ?
      • ASA
      • Sulindac
      • COX - 2 inhibitors
    • Colorectal cancer
      • Cure
      • More effective treatment ?
      • Yes
    •  
    • Colorectal cancer
      • Early diagnosis
      • Screening ?
      • Yes
    • Colorectal cancer - Screening
      • Identify risk groups
      • Inflammatory bowel disease
      • Polyposis coli
      • Cancer family syndrome
      • Known colorectal cancer
      • Known adenomas
    • Colorectal cancer - Screening
      • Inflammatory bowel disease
      • Pancolitis and low age at diagnosis
      • Family history of colorectal cancer
      • Sclerotic cholangitis
      • Best prevention is
      • Surgery !
    • Colorectal cancer - Screening
      • Familiar polyposis coli
      • All known families in register
      • Early endoscopy
      • Gene - mapping
      • Surgery when adenomas occur
    • Colorectal cancer - Screening
      • Cancer family syndrome HNPCC
      • A rare condition ?
      • Gene - mapping
      • Right - sided colon cancer
      • Low age at diagnosis
      • Ovarian and uterus cancer
    • Colorectal cancer - Screening
      • Known colorectal cancer
      • A ‘clean’ colon perioperatively
      • Colonoscopy every 5th year
      • Metachronous cancer ( < 3%)
      • Selection due to age
    • Colorectal cancer - Screening
      • Known adenomas
      • ‘ Clean’ the colon once
      • ‘ High-risk’; - treat as a cancer
      • ‘ Low-risk’; - no more follow-up
      • Selection due to age
    • Colorectal cancer - Screening
      • Known adenomas
      • ‘ High - risk’ group
      • > 3 adenomas
      • > 5 hyperplastic polyps in rectum
      • Size > 1 cm
      • Tubulovillous or villous
      • Dysplasia; severe or malignant
    • Colorectal cancer - Screening
      • Known adenomas
      • ‘ Low - risk’ group
      • < 3 adenomas
      • < 5 hyperplastic polyps in rectum
      • Size < 1 cm
      • Tubular
      • Dysplasia; mild or moderate
    • Screening för kolorektal cancer
      • FOBT
      • Tumörmarkörer i feaces
      • Skopier
    • Screening för kolorektal cancer
      • EU rekommenderar screening
      • Riktlinjerna FoU
      • FOBT ej FoU
      • Skopier
    • Colorectal cancer - Screening
      • Faecal occult blood testing
      • Low sensitivity
      • 40 % cancer missed
      • 80 % adenomas missed
      • ‘ Late stage’ lesions bleed
      • Frequent testing but inexpensive
    • Colorectal cancer - Screening
      • Faecal occult blood testing
      • Minnesota - trial USA
      • Funen - trial Denmark
      • Nottingham - trial UK
      • Gothenburg - trial Sweden
    • FOBT Screening - mortality from CRC Heitson et an. Cochrane Database of Systematic Reviews 2007
    • FOBT screening - total mortality Heitson et an. Cochrane Database of Systematic Reviews 2007
    • Colorectal cancer - Screening
      • Faecal occult blood testing
      • What do we know from these trials ?
      • There is a survival benefit !
      • What type of test ?
      • Annually or biannually ?
    • Colorectal cancer - Screening
      • Flexible sigmoidoscopy
      • Case-control studies
      • J Clin Epidemiol 1988;41:427-34
      • N Engl J Med 1992;326:653-7
      • J Natl Cancer Inst 1992;84:1572-5
    • Colorectal cancer - Screening
      • Flexible sigmoidoscopy
      • Rationale
      • Single sigmoidoscopy at age 60
      • 5 % of colorectal cancers occur before the age of 50
      • 4 % between ages 50-55 years
    • Colorectal cancer - Screening
      • Flexible sigmoidoscopy
      • Rationale
      • Cancers start as an adenoma
      • Small adenomas don't bleed
      • Treatment immediately
    • Colorectal cancer - Screening
      • Flexible sigmoidoscopy
      • Rationale
      • Identify the ‘high’ and ‘low risk’ patient
      • Colonoscopy for a ‘high risk’ patient
      • Follow the ‘high risk’ group every 5th year
    • Flex-sig screening - CRC mortality Atkin et al, Lancet 2010
    • Colorectal cancer - Screening
      • Colonoscopy once ?
      • Why not !
    • Colorectal cancer - Screening
      • Colonoscopy once
      • Incidence Adenomas
      • Cancers
      • Age 50 60 70
    • Colorectal cancer - Screening
      • NordICC
      • Norway, Sweden
      • Poland, Holland
      • Baltic states
      •  50.000
    • Colorectal cancer - Screening
      • FOB - testing
      • the only evidence
      • based technique !
    • Colorectal cancer - Screening
      • How to
      • Implement
      • FOBT – testing ?
    • Colorectal cancer - Screening
      • How to continue
      • Implement it slowly
      • Check quality
      • Must be able to evaluate
      • Surrogate end - points
      • Must be able to stop the process
    •  
    • Colorectal cancer - Screening
      • Stop the experiment
      • if the endpoints
      • are not reached
    • Colorectal cancer - Screening
      • Do we know the endpoints ?
      • We can use surrogate endpoints
    • Colorectal cancer - Screening
      • Surrogate endpoints
      • Compliance  60 %
      • Pos. pred. value FOB - test  12 %
      • Completion rate colonoscopy  85 %
      • Complication at colonoscopy  0.02 %
      • Stage I or II cancer  55 %