Colonoscopy requirements of population screening for colorectal cancer in New Zealand
Terri Green, Ann Richardson, Susan Parry
A national screening programme for bowel cancer has been recommended for New Zealand. This involves a test called the faecal occult blood test (FOBTi or FIT) which would be offered to people aged 50-74 every 2 years. The test is not 100% accurate and if it shows positive, a colonoscopy which is a complete examination of the bowel, is required to determine presence of cancer (or adenomas which could develop into cancer). Colonoscopies are also required to monitor adenomas found. This paper estimates the volume of colonoscopies required if a national bowel screening programme using the immunochemical faecal occult blood test (FOBTi) for the initial screen for people aged 50-74 (currently being piloted in Waitemata) is introduced in New Zealand. A national bowel cancer screening programme will require a large volume of colonoscopies, estimated at 18,000 in the first year rising to 28,000 after 20 years. Services will need to expand to meet this demand, in order to deliver the colonoscopies following a positive FOBTi, in a timely fashion to confirm diagnosis, whilst also maintaining services for people with symptoms, or at higher risk. Monitoring of small adenomas will need to be carefully managed.