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New Tests in Gastroenterology

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  1. New Tests in Gastroenterology Stephen Bridger ACB Meeting 10/11/2005

  2. Gastroenterology • Too Busy • Too Many patients • IBS 14 - 24% of adult population, + 28% of referrals to GI clinics • Too Many Investigations • Doubling of endoscopy workload in last 10 yrs • Non Specific nature of GI symptoms • Even alarm symptoms such as rectal bleeding common (1 in 7 adults/week) + poorly predictive of significant GI pathology • Unable to predict which of our chronic patients will relapse and when.

  3. “Would you mind very much if I went in before you? You’ve only a sore throat and I’ve diarrhoea”

  4. Lundberg JO et al. (2005) Technology Insight: calprotectin, lactoferrin and nitric oxide as novel markers of inflammatory bowel disease Nat Clin Pract Gastroenterol Hepatol2:96–102 doi:10.1038/ncpgasthep0094

  5. Calprotectin • 35 KDa Calcium and Zinc binding protein found in neutrophils, monocytes, and macrophages • Up to 60% of the total cytosolic protein content of neutrophils • First Described in 1980 • Initially called L1 protein • Antimicrobial and Anti-tumour activity • reduces local zinc concentrations, and inhibits zinc dependent metalloproteinases

  6. Clinical Use • Resists metabolic degradation • measured in stool, plasma, CSF, sputum, amniotic fluid • Stool samples can be sent by post, then frozen and batch analysed • Approx £10 per test • Upper limit of normal in stool is 10mg/l • As little as 5gm stool sample required

  7. Clinical Uses • extensively validated, showing consistent abnormalities in patients with IBD, colorectal carcinoma, and nonsteroidal enteropathy • Proposed as a useful outpatient screening test for organic small bowel or colorectal pathology. May be particularly useful in children. • Proposed as an IBD monitoring test, can predict steroid refractory disease, or which “well patients” are likely to relapse. Potential for monitoring the efficacy of new therapeutic regimes.

  8. General Background • Levels relatively unaffected by GI bleeding • need > 100mls of blood per day to increase calprotectin level by 6mg/l • In active Crohn’s disease, levels of calprotectin up to 40,000 mg/l reported

  9. Guidelines for the investigation of chronic diarrhoea,Gut 2003 • “Stool markers of gastrointestinal inflammationsuch as lactoferrin and, more recently,calprotectin, areof considerable research interest but, as yet, these have notbeen introduced into clinical practice.”

  10. A simple method for assessing intestinal inflammation in Crohn's diseaseTibble et al Gut 2000 • 22 patients: fecal calprotectin compared with 4 day 111Indium White Cells • Good correlation (r = 0.8 , P<0.0001) • 116 patients with known Crohn’s disease, calprotectin was compared with healthy controls • 220 consecutive patients attending a GI clinic, 31 newly diagnosed Crohn’s disease, 159 patients with IBS...

  11. Calprotectin: Crohn’s versus Controls

  12. Calprotectin compared with CRP

  13. Use of surrogate markers of inflammation and Rome criteria to distinguish organic from nonorganic intestinal diseaseTibble et al Gastroenterology 2002 • Prospective study: 602 new GI referrals • 4 Gastroenterologists blinded to the results of calprotectin and permeability, other investigations determined by Physicians • 263 patients diagnosed with organic disease

  14. Referral Symptoms

  15. Calprotectin Levels in the Different Diagnostic Groups

  16. Sensitivity/Specificity for Organic and Non-Organic Disease

  17. Odds Ratios for Organic and Non-organic Disease

  18. Diagnostic accuracy of fecal calprotectin in distinguishing organic causes of chronic diarrhoea from IBS: A prospective study in adults and children. Carroccio et al Clin Chem Jun 2003 • Prospective study 120 patients • Raised Calprotecin levels predicted pts with IBD with 100% sensitivity and 95% specificity • Diagnostic accuracy higher in children • Coeliac disease was the commonest cause of false negatives

  19. Fecal calprotectin - a useful screening test for inflammation of the colon in children.Fagerberg et al DDW 2003 • 36 children : calprotectin prior to colonoscopy • 22 of the children had colitis on Hxpath + endoscopic criteria: • Mean calprotectin 349 (15.4 - 1860 mg/L) • Sensitivity & Positive predictive value 95% • Specificity of 93%

  20. Fecal Calprotectin as an aid to Diagnosis in intestinal inflammationDolwani et al DDW 2003 • 65 patients with abdo pain + diarrhoea • All referred for Barium follow through • 15 false negatives: 6 IBD, 4 IBS, 5 uncertain

  21. Fecal Calprotectin in steroid dependent Colitis. An indicator of clinical responseAtkinson DDW 2003 • 27 patients with steroid dependent colitis in remission • Calprotectin checked at 0, 8 and 16 weeks • steroids reduced at 2 weekly intervals until relapse or cessation • Mean Calprotectin at Time Zero was 6 x higher in those patients who Relapsed (P = 0.0009) • “CPT may differentiate between pts with merely symptomatic response and those with genuine mucosal healing- failure to lower CPT sufficiently may indicate the need for a trial of a different therapy”

  22. Surrogate markers of intestinal inflammation are predictive of relapse in patients with inflammatory bowel disease Gastroenterology 2000;119:15-22

  23. Subclinical intestinal inflammation: An inherited abnormality in Crohn’s disease relatives?Gastroenterology June 2003

  24. Effect of Pentavac and MMR vaccination on the intestineGut 2002 816-17 • 109 consecutive infants attending an Iceland Vaccination clinic had fecal calpro taken 1 week prior and 2 and 4 weeks after Pentavac (12 months) and MMR (18 months) • No differences at any time of study • “MMR very unlikely to cause ‘autistic enterocolitis’”

  25. Calprotectin versus FOB in Bowel Cancer • FOB screening in asymptomatic patients has reduced bowel ca mortality by 15-33% • Detection threshold about 2-4 mls of blood/100g stool but tumours bleed intermittently and polyps may not bleed at all • Sensitivity of FOB may be as low as 26%

  26. Faecal Calprotectin and FOB tests in the diagnosis of colorectal carcinoma and adenoma. Gut 2001 49(3):402-8 • 3 FOBs and 1 stool calprotectin sample • Three groups • 96 Controls (healthy volunteers) • 62 consecutive patients with newly diagnosed bowel cancer • 233 consecutive patients referred for colonoscopy for polyp follow up, cancer surveillance, anaemia

  27. Calprotectin vs FOB

  28. Faecal Calprotectin in the Different Diagnostic Groups

  29. Fecal Calprotectin levels in a high risk population for colorectal neoplasia Kronberg et al Gut 2000 (46) 795 -800

  30. Calprotectin and Cancer

  31. Conclusions • Calprotectin has significant advantages over guaiac based FOB testing • Higher sensitivity for colorectal ca • More likely to detect patients with Dukes A + B • More likely to detect patients with rectal and right sided tumours • Single test rather than 3 samples • No dietary restrictions

  32. Conclusions 2 • Sensitivity >95% for detecting patients with IBD • Failure to lower CPT predicts those patients with steroid refractory disease (even if the patient has had a good symptomatic response to steroids) • Asymptomatic patients with IBD with CPT > 50mg/l have a 90% probability of relapse in the next 12 months • CPT reduction in IBD treated patients appears to correlate with endoscopic mucosal healing • CPT levels much more clinically useful in IBD than any of the currently used systemic immune tests (CRP, ESR, Igs, Plts)

  33. The Future? • GI OPD screening • Organic versus non-organic • Investigate versus observe • Population based bowel cancer screening • Selected high risk groups • IBD monitoring • Availability ?