If you’re having an evaluation for colorectal cancer (diagnostic work-up) at Seattle Cancer Care Alliance, most likely you’ve already been diagnosed with colorectal cancer. Your referring doctor based your initial diagnosis on screenings, examinations, and tests that may have included the following:
- Medical history, family history, and physical exam—Your doctor asks tquestions about symptoms and risk factors, including family history. He or she carefully examines your abdomen to feel for masses or enlarged organs and examines the rest of your body. This may include a digital rectal examination. The doctor inserts a lubricated, gloved finger into your rectum to feel for abnormal areas or masses. This exam can be a little uncomfortable but is very quick.
- Fecal occult blood test—This simple, at-home test checks for blood in the stool. Studies have proved that when this test is done every one to two years in people ages 50 to 80, it reduces the number of deaths due to colorectal cancer by as much as 30 percent.
- Flexible sigmoidoscopy—Your doctor looks at your rectum and lower colon using a thin, lighted tube called a sigmoidoscope. A sigmoidoscopy can find precancerous and cancerous polyps and tumors. Your doctor may perform a biopsy (see below) by removing all or part of a polyp or tumor (a tissue sample) through the sigmoidoscope for examination under a microscope. Studies suggest that regular screening with sigmoidoscopy after age 50 can reduce the number of deaths from colorectal cancer.
- Colonoscopy—Using a thin, lighted tube similar to the sigmoidoscope but longer, your doctor examines the inside of your entire colon for polyps, tumors, and abnormal tissue. This procedure allows your doctor to see much further into the colon than during a sigmoidoscopy. Biopsies are performed on any polyps or tumors.
- Biopsy—A pathologist, a doctor who specializes in evaluating tissue samples, uses a microscope to look at the tissue sample removed from your colon or rectum. The pathologist can see whether the cells are cancer or not. A biopsy provides a definitive diagnosis.