Colonoscopic prioritization in colorectal carcinoma screening using quantitative immunochemical faecal occult blood test: a pilot study

BACKGROUND: Screening for colorectal cancer (CRC) improves outcomes and reduces its incidence. However, population-based screening in Malaysia continues to be a challenge, in view of cost and limited availability of colonoscopic skills and facilities. Conventional qualitative faecal occult blood tests help to prioritize those who require earlier colonoscopies, but cannot distinguish between benign and malignant causes. Recently, quantitative immunochemical faecal occult blood tests (qFOBT) have demonstrated some discriminatory ability in distinguishing benign and malignant causes. We aim to assess feasibility of qFOBT as a tool for stratification of colonoscopic priority in asymptomatic patients.
METHODS: A health awareness exhibition was held in a major shopping complex in Kuala Lumpur on 6 and 7 Feb 2010. All asymptomatic individuals> 40 years, and those < 40 with family history of CRC, were invited to participate. Eligible participants were given a questionnaire and screened using a qFOBT. A faecal haemoglobin level of 100 - 199 ng/mL was considered moderately positive, while a level of 200 ng/mL or more was strongly positive. Participants with a strongly positive qFOBT result were scheduled for a colonoscopy within the month, while those who were moderately positive were scheduled within 3 months.
RESULTS: A total of 125 (82%) participants returned the qFOBT kit, of which 70 (56%) were male. The median age was 54 years. Majority of the participants were Chinese (60%), followed by Malay (25%), Indian (12%) and others (3%). Twelve (10%) participants were tested positive and were advised to undergo colonoscopy but 9 (75%) declined colonoscopy and further investigations citing lack of time as the reason. Of the 3 participants (all in the moderately positive group) who underwent colonoscopy, 2 had a family history of CRC. Colonoscopic findings revealed haemorrhoids in one participant and two participants had histologically proven benign sigmoid colonic polyps.
CONCLUSION: The use of qFOBT as a tool to screen and prioritize asymptomatic patients for early colonoscopy in CRC screening is logistically feasible. However, in order for it to be effective, measures to improve compliance to colonoscopy need to be taken.