Origins and evidence
In late-1960s New York, Hiromi Shinya and William Wolff used fiberoptic scopes to view the entire colon and remove polyps without surgery (Wolff & Shinya, 1973). Most colorectal cancers grow slowly from adenomatous polyps, and removing them cut cancer incidence sharply (Winawer et al., 1993) and roughly halved deaths over the long term (Zauber et al., 2012). This page is educational and not a personal diagnosis.
Who should get one
Korea's national program offers annual stool testing from age 50 and colonoscopy when positive. Talk to a doctor sooner about rectal bleeding, black stools, unexplained anemia or weight loss, lasting bowel-habit changes, a family history of colorectal cancer, or inflammatory bowel disease. Recurrent cramps without warning signs may be irritable bowel syndrome.
Prep, procedure and quality
Avoid seeds, whole grains and seaweed for two to three days, then take a split-dose prep the evening before and the morning of the exam until output is clear yellow liquid. No driving after sedation. Bleeding and perforation are rare but watch for heavy bleeding or severe pain after polyp removal. Quality matters: low adenoma detection rates predict interval cancers (Kaminski et al., 2010), and each one-point rise lowers risk by about 3% (Corley et al., 2014).
Screening only works if you go
In the NordICC trial, people invited to colonoscopy had about 18% lower 10-year cancer risk, smaller than hoped, largely because only about 42% attended (Bretthauer et al., 2022). The best test is the one you actually take.
This article is general health information and is not a substitute for diagnosis or treatment. If symptoms persist, see a doctor.
FAQ
- At what age should I start?
- Korea starts with stool testing at 50; see a doctor earlier if you have symptoms or family history.
- Do I need another scope after polyp removal?
- Yes. Timing depends on the number, size and type of polyps.
Sources reviewed: 2026-11-09
References
- Wolff, W. I., & Shinya, H. (1973). Polypectomy via the fiberoptic colonoscope. New England Journal of Medicine, 288(7), 329–332. Early report of removing polyps through the fiberoptic colonoscope.
- Winawer, S. J., Zauber, A. G., Ho, M. N., O'Brien, M. J., Gottlieb, L. S., Sternberg, S. S., … Stewart, E. T. (1993). Prevention of colorectal cancer by colonoscopic polypectomy. New England Journal of Medicine, 329(27), 1977–1981. National Polyp Study: removing adenomas markedly lowers cancer incidence.
- Zauber, A. G., Winawer, S. J., O'Brien, M. J., Lansdorp-Vogelaar, I., van Ballegooijen, M., Hankey, B. F., … Waye, J. D. (2012). Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. New England Journal of Medicine, 366(8), 687–696. Long-term follow-up: about 53% fewer colorectal cancer deaths.
- Bretthauer, M., Løberg, M., Wieszczy, P., Kalager, M., Emilsson, L., Garborg, K., … Kaminski, M. F. (2022). Effect of colonoscopy screening on risks of colorectal cancer and related death. New England Journal of Medicine, 387(17), 1547–1556. Randomized NordICC trial: invitation effect smaller than hoped, low uptake.
- Kaminski, M. F., Regula, J., Kraszewska, E., Polkowski, M., Wojciechowska, U., Didkowska, J., … Butruk, E. (2010). Quality indicators for colonoscopy and the risk of interval cancer. New England Journal of Medicine, 362(19), 1795–1803. Low adenoma detection rates predict interval cancers.
- Corley, D. A., Jensen, C. D., Marks, A. R., Zhao, W. K., Lee, J. K., Doubeni, C. A., … Quesenberry, C. P. (2014). Adenoma detection rate and risk of colorectal cancer and death. New England Journal of Medicine, 370(14), 1298–1306. Each 1-point ADR rise linked to about 3% lower cancer risk.
- 국립암센터 국가암정보센터. (n.d.). 국가암검진: 대장암. Korea's national screening: stool test from 50, colonoscopy if positive.