What “causes” colorectal cancer?

The exact causes of colorectal cancer are unknown, but half of all people develop colorectal polyps. Polyps are small growths that can become cancerous over time. Finding pre-cancerous polyps decreases the risk of colorectal cancer.


What is a polyp?

  • Polyps are small growths in colon or rectum, which could become cancerous over time. If a polyp is found early, it can be removed with a colonoscopy screening test before it turns into cancer.
  • Most polyps do not cause symptoms; however, larger polyps are more likely to be bleed when stool passes through the colon. This blood can be in your bowel movement. This blood can be detected in your stool with a FOBT screening test.


Can I get colorectal cancer if I don’t have polyps?

Most adults cannot get colorectal cancer if they do not have polyps. Less than 5 out of 100 colorectal cancers occur without any polyps (growths). Colorectal cancer without polyps usually occurs in people who are at increased risk for colorectal cancer because of either a hereditary syndrome called hereditary non-polyposis colon cancer or long-term inflammatory bowel disease.


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