Population screening: Discussion
Unresolved issues[edit source]
There is currently insufficient evidence from appropriately designed studies to determine the following:
- the diagnostic performance of non-FOBT faecal or blood-based cancer-specific biomarker assays, and whether these are influenced by participant age, sex, or risk of colorectal cancer
- the effectiveness and cost-effectiveness of population screening based on colonoscopy, CT colonography, faecal DNA biomarkers, or blood or plasma cancer-specific biomarkers such as DNA
- the effectiveness and cost-effectiveness of population screening based on combinations of screening modalities
- the effectiveness and cost-effectiveness of population screening in people younger than 50 years or older than 75 years.
Other unresolved issues include:
- whether the inappropriately high rate of colonoscopy in Australia reduces effectiveness of the NBCSP
- how the NBSCP should respond to the changing epidemiology of colorectal cancer, including incidence at younger age and changes in distribution of cancer within the large bowel
- how to maximise participation rates.
Studies currently underway[edit source]
No evidence was identified from randomised controlled trials (RCTs) evaluating colonoscopy, computed tomography (CT) colonography, or cancer-specific faecal or blood biomarkers. Three RCTs evaluating colonoscopy-based screening are in progress:
- The Northern-European Initiative on Colorectal Cancer (NordICC)
- Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM)
- Colorectal Cancer Screening in Average-risk Population: Immunochemical Fecal Occult Blood Testing Versus Colonoscopy.
Only one of these RCTs includes a no-screening arm.
Future research priorities[edit source]
Future research opportunities include:
- studies assessing the place of combinations of screening tests (e.g. iFOBT every 2 years and flexible sigmoidoscopy every 10 years (at ages 55, 65 and 75 years)
- studies on screening tailored to the presence of special risk factors (e.g. adjusting the starting age of screening, using more sensitive iFOBT conditions or combining screening tests tailored to factors such as sex, BMI, history of cigarette smoking)
- evaluation of the performance characteristics of new versions of tests for faecal and blood-based cancer-specific biomarkers.
- Bretthauer M, Kaminski MF, Løberg M, Zauber AG, Regula J, Kuipers EJ, et al. Population-Based Colonoscopy Screening for Colorectal Cancer: A Randomized Clinical Trial. JAMA Intern Med 2016 Jul 1;176(7):894-902 Available from: http://www.ncbi.nlm.nih.gov/pubmed/27214731.
- ClinicalTrials.gov. Colonoscopy vs fecal immunochemical test in reducing mortality from colorectal cancer (CONFIRM) [NCT01239082]. [homepage on the internet]; 2016 Available from: https://clinicaltrials.gov/ct2/show/NCT01239082.
- Quintero E, Castells A, Bujanda L, Cubiella J, Salas D, Lanas Á, et al. Colonoscopy versus fecal immunochemical testing in colorectal-cancer screening. N Engl J Med 2012 Feb 23;366(8):697-706 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22356323.