Begin colorectal screening around 45–50, using a fecal immunochemical test or colonoscopy
A low-cost fecal occult blood test every year or two reduced colorectal cancer deaths by about 16%; among people who attended at least one round, the reduction was 25%. Inviting people for one colonoscopy reduced their 10-year colorectal cancer incidence from 1.20% to 0.98%.
What it takes
In China, stool testing costs a few dozen renminbi every 1–2 years. Colonoscopy costs several hundred to over RMB 1,000; a negative result supports a 10-year interval. Set aside a day beforehand for bowel preparation.
What you may gain
A Cochrane pooled analysis found 16% lower colorectal cancer mortality with fecal occult blood screening: RR 0.84, 95% CI 0.78–0.90. Among people attending at least one round, mortality was about 25% lower (RR 0.75). In the NordICC randomized trial, inviting people for colonoscopy reduced 10-year colorectal cancer incidence from 1.20% to 0.98%: RR 0.82, 95% CI 0.70–0.93.
Context & considerations
There is debate. NordICC analyzed people invited for colonoscopy, whether or not they attended. Colorectal cancer mortality was 0.28% versus 0.31% (RR 0.90, 95% CI 0.64–1.16), a difference compatible with chance. The source interprets this as suggesting that colonoscopy's mortality benefit was previously overestimated; stool testing has stronger direct mortality evidence. Guidelines differ on starting age, generally 45–50. A family history warrants starting earlier.
Research & references
Hewitson P et al. (2007). Screening for colorectal cancer using the faecal occult blood test, Hemoccult. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.CD001216.pub2 ; Bretthauer M et al. (2022). Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death. New England Journal of Medicine. https://doi.org/10.1056/NEJMoa2208375