Regular bowel movements and the absence of pain do not mean a person is free from the risk of colorectal cancer. Polyps that can turn into cancer often grow without symptoms. One specialist said polyps are found in four or five out of every 10 adults, underscoring the importance of regular colonoscopies.
Colorectal Screening Rate at 40.3%, Colonoscopy to Be Adopted From 2028
The government reviewed and approved the Fifth Comprehensive Plan for Cancer Control, covering 2026 to 2030, at a meeting of the National Cancer Control Committee on the 24th, the Ministry of Health and Welfare said on the 25th. The core change is a shift in the national colorectal cancer screening program from fecal occult blood testing to colonoscopy.
Under the current system, adults aged 50 and over undergo an annual fecal occult blood test that checks for traces of blood in stool. Those with abnormal results then receive a colonoscopy.
From 2028, the government plans to offer a colonoscopy every 10 years as the primary screening test for adults aged 45 to 74.
The colorectal cancer screening rate stands at 40.3%, the lowest among major cancer screenings, according to government figures. By contrast, a 2024 survey by the National Cancer Center found that 66.2% of respondents preferred a colonoscopy, roughly double the 33.8% who favored a fecal occult blood test.
A colonoscopy allows doctors to examine the inside of the bowel directly and remove polyps that could develop into cancer.
Polyps Found in 40% to 50% of Adults, Even Without Symptoms
Lee Won-kyung, a professor of radiology, recently discussed the risks of colorectal polyps and the importance of regular screening on the YouTube channel "Lee Won-kyung, the Doctor Who Finds Cancer," which has about 350,000 subscribers.
Lee said people undergo health checkups "to find lesions that can turn into cancer early, while there are no symptoms." The point, the professor said, is that having no trouble with bowel movements is not a reason to feel safe.
According to Lee, polyps are found in about 40% to 50% of adults who undergo a colonoscopy.
A polyp is a lesion in which the lining of the colon protrudes like a lump. It can form when abnormal cells emerge as the cells of the bowel lining divide and regenerate.
Not all polyps progress to cancer, however. Adenomatous polyps can develop into colorectal cancer over time, while hyperplastic polyps generally carry a low risk of becoming cancerous. For inflammatory polyps, the risk is assessed in light of underlying conditions such as inflammatory bowel disease.
Complications can also occur when polyps are removed. Particular care is needed over the risk of perforation, or a hole in the bowel, when large polyps are resected or when adhesions are present from previous abdominal surgery.
Still, Lee said fear of complications is no reason to avoid the test. "Not getting a colonoscopy because you are afraid of perforation is pretty much like not riding in a car because you are afraid of traffic accidents," the professor said.
Removing a Polyp Is Not the End: Diet and Follow-Up Matter
Having a polyp removed during a colonoscopy does not mean the monitoring is over.
Lee advised that the timing of the next examination should be set based on the type and number of polyps removed, as well as family history. Those who had multiple polyps or who have a hereditary condition may need follow-up tests at shorter intervals than the standard screening cycle.
Improving eating habits also matters. Lee said eating enough fiber-rich foods such as vegetables helps bowel movement and reduces the time the colon lining is exposed to harmful substances.
Diets heavy in processed meat or low in fiber, by contrast, need to be reconsidered, the professor said.
Because some polyps take years to turn into colorectal cancer, detecting lesions before symptoms appear is critical. Experts stress that recommended screening intervals should be followed even when bowel habits appear normal.
