1.3 Early detection
The NBCSP invites people starting at age 50 and continuing to age 74 (at average risk and asymptomatic) to screen for bowel cancer using a free, simple test at home.
NBCSP participants with screen-detected bowel cancer are more likely to be diagnosed at a less advanced stage than those who did not participate (Cancer Council Australia 2020). NBCSP participants with screen-detected bowel cancer had a lower risk of bowel cancer mortality compared with those who were diagnosed outside of the program (9.6 per cent vs 23.8 per cent) (AIHW 2018b). Bowel cancer screening on a population basis significantly reduces mortality and morbidity (Cancer Council Australia 2020).
Cancer Council Australia Colorectal Cancer Guidelines Working Party (2019) recommends the following.
Category 1: Near average risk
For people with category 1 risk of colorectal cancer, an immunochemical faecal occult blood test (iFOBT) should be performed every two years from age 50 to age 74.
Full examination of the large bowel by colonoscopy is recommended for people who have a positive iFOBT.
Category 2: Moderately increased risk
For people with category 2 risk of colorectal cancer, offer iFOBT every two years starting at age 40, then colonoscopy every five years starting at age 50. CT colonography may be offered if colonoscopy is contraindicated.
Category 3: High risk
For people with category 3 risk of colorectal cancer, offer iFOBT every two years starting at age 35, then colonoscopy every five years from age 45 to age 74. CT colonography may be offered if colonoscopy is not feasible.
Consider referral to a familial cancer service for further risk assessment and possible genetic testing.
Refer to a bowel cancer specialist to plan appropriate surveillance and management.
First-degree relatives of people with colorectal cancer who fall into the category 2 (moderate risk) group (where a relative is diagnosed under 55 years of age or where there are multiple first-degree relatives with colorectal cancer) should be advised to see their general practitioner with a view to referral for a colonoscopy if appropriate.
All other relatives should be advised to follow the average risk guidelines, including participating in the National Bowel Cancer Screening Program.
