How does the doctor know that i have colon cancer?

Biopsy: Colon cancer is most frequently diagnosed following an endoscopic procedure such as a colonoscopy or flexible sigmoidoscopy. The cancer is biopsied at that time, leading to the diagnosis.

Biopsy: A biopsy is needed to be sure and start treatment, but other ways it may be suspected is a positive stool blood test, blood tests, and ct scan.

Colonoscopy: Colonoscopy with biopsy if a mass is seen.

Most common: Unfortunately, the most common cause of a mass in the colon or rectum, found on either physical examination, colonoscopy or another study such as ct, is cancer. The only way to confirm the diagnosis is by obtaining a small sample of tissue (biopsy) and having a pathologist examine it under a microscope.