seema qaiyumi md georgetown university hospital february 17 2009 l.
Skip this Video
Loading SlideShow in 5 Seconds..
Seema Qaiyumi, MD Georgetown University Hospital February 17, 2009 PowerPoint Presentation
Download Presentation
Seema Qaiyumi, MD Georgetown University Hospital February 17, 2009

Loading in 2 Seconds...

play fullscreen
1 / 22

Seema Qaiyumi, MD Georgetown University Hospital February 17, 2009 - PowerPoint PPT Presentation

  • Uploaded on

Comparative Evaluation of Immunochemical Fecal Occult Blood Tests for Colorectal Adenoma Detection A nnals of Internal Medicine : February 3, 2009 Seema Qaiyumi, MD Georgetown University Hospital February 17, 2009 Background Colorectal Cancer is the 3 rd most common cancer in the world.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Seema Qaiyumi, MD Georgetown University Hospital February 17, 2009' - lotus

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
seema qaiyumi md georgetown university hospital february 17 2009

Comparative Evaluation of Immunochemical Fecal Occult Blood Tests for Colorectal Adenoma DetectionAnnals of Internal Medicine : February 3, 2009

Seema Qaiyumi, MD

Georgetown University Hospital

February 17, 2009

  • Colorectal Cancer is the 3rd most common cancer in the world.
  • 1 million new cases and >500,000 deaths per year.
  • Most cases are sporadic and develop from removable precancerous lesions (adenomas) and curable early stage cancer.
  • Screening has a high potential for reducing morbidity and mortality.
  • RCT demonstrate reduced mortality with guaiac based Fecal Occult Blood Testing (FOBT) followed by sigmoid or colonoscopy if FOBT is positive.
fecal occult blood testing
Fecal Occult Blood Testing
  • Guaiac based
  • Chemical reaction on a paper card which detects pseudoperoxidase activity of heme or hemoglobin
  • Limitations
    • Not specific for human hemoglobin
    • False +/- results from compounds in medications or food
    • (undercooked red meat, Vitamin C supplements)
    • Low diagnostic performance for precursors
  • Advantages
    • Low cost
    • Easy to do in physician’s office with adequate training for reading and interpretation
immunochemical fobt
Immunochemical FOBT
  • Use specific antibodies against human blood components to overcome diet/medication restrictions
  • Quantitative FOBTs
  • Qualitative FOBTs
    • Use immunochromatographic technology to allow simple office based analysis
    • Differences exist that may influence the diagnostic performance (especially in detection of precursor lesions)
      • Antibodies used
      • Different detection limits
study aim
Study Aim

Determine and compare performance characteristics of different qualitative immunochemical FOBTs for the detection of colorectal adenomas in a large sample of women and men undergoing screening colonoscopy

  • Part of ongoing screening study including 20 GI practices in SW Germany from January 2006 -December 2007
  • Patients Included: 1319 patients undergoing routine screening colonoscopy
  • Patients excluded
    • Visible rectal bleeding or preceding + FOBT
    • Inflammatory Bowel Disease
    • Colonoscopy within 5 years
    • Stool samples collected after colonoscopy
    • Inadequate bowel prep
    • Incomplete colonoscopy
    • Histologically confirmed diagnosis of CRC
    • Non defined polyps (no histology reports available)
    • Pseudopolyps (likely UC/IBD)
    • President Bush
  • Stool collection
    • Participants were given 1 test card for guaiac-based FOBT, a small 60mL container for stool collection, collection tissue and detailed instructions for stool collection
    • Samples were collected at home using specific instructions for collection and storage
    • Samples were brought on the day of colonoscopy and shipped on dry ice to a central lab for analysis
stool tests
Stool Tests
  • Done by PA’s who were blinded to colonoscopy and stool guaiac results
  • Six Immunochemical FOBT’s used
    • Bionexia FOB-plus (Gottingen, Germany)
    • PreventID CC (Bensheim, Germany)
    • ImmoCARE-C (Voerde, Germany)
    • FOB advanced (Ahrensburg, Germany)
    • QuickVue iFOB (San Diego, California)
    • Bionexia Hb/Hp Complex (Gottingen, Germany)
data analysis
Data Analysis
  • Two independent technicians interpreted all FOBT tests
  • Interoobserver reliability was very good (ĸ statistics)
  • Sensitivity and Specificity of each test to detect adenoma was calculated
  • Based on duration of sample storage prior to testing, no general trend for sensitivity or specificity
  • Whether stool samples were frozen or not did not appear to cause relevant differences based on sensitivity analysis
  • Stool tests are an integral component of CRC screening
  • Useful in patients who are unwilling/unable or when health care resources are limited
  • Marked differences were found when comparing multiple qualitative immunochemical FOBTs
  • Promising results found for only 2 tests:
    • immoCARE-C (25% - 96.7%)
    • FOB advanced (27% - 92.9%)
    • Higher sensitivities found for distal, large and multiple adenomas
other studies
Other Studies
  • Magstream 1000/Hem SP (Tokyo, Japan) compared to colonoscopy (n=21,805)
    • Quantitative immunochemical FOBT based on magnetic agglutination
    • Sensitivity 22.3% - Specificity 95.5%
  • FlexSure OBT (Palo Alto, CA) compared to sigmoidoscopy (n=584)
    • Limited to distal lesions only
    • Sensitivity 29.5% - Specificity 97.3%
  • Studies comparing multiple immunochemical FOBT’s in parallel are few and have small numbers
study strengths
Study Strengths
  • Multiple immunochemical FOBTs compared in parallel
  • All participants had colonoscopies, regardless of FOBT outcome
  • FOB testers and colonoscopy MD’s were blinded to test results
  • Assessed test performance characteristics in the target population for screening (age and risk profile)
  • Distribution of findings (% of adenomas) was in accordance with other studies
study limitations
Study Limitations
  • Stool from only 1 day was collected
    • Underestimates sensitivity
    • Overestimates specificity
  • Stool was stored frozen instead of used fresh
  • Bias: Participants undergoing screening colonoscopy may be more health conscious than the general population
  • Limited by the accuracy of screening colonoscopy to detect precancerous lesions
  • Qualitative immunochemical FOBT could be an option for future CRC screening
  • Careful evaluation of each test is needed given the differences among tests
  • Only 2 of the tests showed specificity needed to become part of routine testing of average risk populations
  • Hundt, Sabrina MSc; Haug, Ulrike PhD; Brenner, Hermann MD, MPH. Comparative Evaluation of Immunochemical Fecal Occult Blood Tests; Annals of Internal Medicine. February 3, 2009.
  • Allison JE, Sakoda LC, Levin TR, Tucker JP, Tekawa IS, Cuff T, et al. Screening for colorectal neoplasms with new fecal occult blood tests: update on performance characteristics. Journal of the National Cancer Institute. 2007. 99:1462-70.
  • Morikawa T, Kato J, yamaji Y, Wada R, Mitsushima, T, Shiratori Y. A comparison of the immunochemical fecal occult blood test and total colonoscopy in the assympomatic population. Gastroenterology. 2005. 129: 422-8.
  • Ferlay J, Bray F, Pisani, P, Parkin DM. GLOBOCAN 2002: Cancer Incidence, Mortality and Prevalence worldwide. IARC Cancer Base No 5. Version 2.0. Lyon France. IARC Pr 2004.
  • Arnold CN, Goel A, Blurm HE, Boland CR. Molecular pathogenesis of colorectal cancer; implications for molecular diagnosis. Cancer. 2005. 104: 2035-47.
  • Hewitson P, Glasziou P, Irwig L, Towler B, Watson E. Screening for colorectal cancer using the fecal occult blood test, Hemoccult. Cochrane Database. Systematic review 2007: CD001216.
  • Jaffe RM, Kasten B, Young DS, MacLowry JD. False-negative stool occult blood tests caused by ingestion of ascorbic acid (Vitamin C). Annals of Internal Medicine. 1975; 83: 824-26.