Diagnosis typically begins with a thorough medical history and physical examination. A digital rectal exam (DRE) can often detect abnormalities in the rectum. Additional diagnostic tests may include a colonoscopy, where a long, flexible tube with a camera is used to visualize the inside of the rectum and colon. Biopsies can be taken during this procedure to determine if the tumor is malignant. Imaging tests such as CT scans, MRI, and PET scans can also help in assessing the extent of the disease.
