Prevention & Screening

Preventing Colorectal Cancer

Many colorectal cancers are preventable through early detection and lifestyle changes. Unless you have other risk factors, such as a family history of polyps or colorectal cancer, regular screenings for polyps should begin at age 45*. Other preventive measures include:

  • Eating a diet low in fat (especially animal fat) and high in fiber from foods like vegetables.
  • Staying physically active and maintaining a healthy weight.
  • Not smoking and if you do smoke, stop. Swedish offers a smoking cessation program (PDF).
  • Limiting alcohol consumption to one or two drinks a day.
  • * It is recommended that patients check with their insurance company to confirm coverage.

Learn more about colon cancer:


Colonoscopy remains the gold standard for colorectal cancer screening. Colonoscopy helps detect the polyps that are predecessors of colon cancer. Finding and removing these polyps prevents the development of colorectal cancers in nearly all cases. If cancer is already present, colonoscopy can help find it early enough for successful treatment.

Physicians at Swedish have specialized training and expertise in screening and diagnosing colorectal cancer. Colonoscopy remains the gold standard for screening. At Swedish, colonoscopies are performed thousands of times a year by colorectal surgeons and gastroenterologists—making Swedish's colorectal cancer screening program the largest in the Northwest.

Learn more about Colonoscopy

Genetic screening can help doctors better tailor colon cancer screening tests and procedures

Genetic counseling and test, which is offered through the SCI’s Hereditary Cancer Clinic, focuses on patients and families at risk for hereditary cancers, including colorectal cancers.

The results of genetic testing can significantly influence a patient’s appropriate screening tests and medical procedures for relatives who may be at risk of cancer.

Other tests for detecting polyps and/or colorectal cancer include:

Fecal Occult Blood Test (FOBT)

As polyps or colorectal tumors grow, they sometimes bleed into the intestine. Benign conditions like hemorrhoids can also cause blood in the stool. Regardless of the cause, the blood in the stool may not always be visible.

The FOBT is a chemical test that detects trace amounts of blood in the stool. Your physician will give you a kit to use at home that includes detailed instructions.

How it works: Beginning two or three days before you take your home test, avoid turnips, radishes, horseradish, red meats, vitamin C, iron supplements, aspirin and other anti-inflammatory medications. They may interfere with test results. Be sure to eat plenty of fiber-rich foods such as lettuce, spinach, corn, apples, prunes, grapes and bran.

The next step is to collect two small stool samples from three consecutive bowel movements. The instructions in the kit will tell you how to use the applicator to apply a thin stool smear onto a slide-like card. Once the samples have been collected, a developer solution is applied. If blood is present in the sample, the card containing the stool smear will change color. Some kits come with developer solution that allow you to test the samples yourself. Other kits require that you return the samples to your doctor — in person or by mail — within four days of collecting them, so they can be tested in a lab.

Flexible Sigmoidoscopy

This short, relatively painless procedure allows the physician to examine the inside of the rectum and the lower part of the colon with a sigmoidoscope, a thin and flexible tube with a light and lens for viewing. Because the flexible sigmoidoscopy only inspects the lower part of the colon, a colonoscopy may be needed if there is a concern that a polyp or cancer may be lurking higher in the colon.

How it works: Prior to the exam, your doctor will provide instructions for cleansing you bowel. The rectum and lower colon need to be free from stool in order to perform the test.

During the procedure, which takes five to 10 minutes, you will lie on your side. Your physician will insert and guide the sigmoidoscope into your rectum and lower colon to examine the lining for polyps or signs of cancer. The physician can view your colon through the sigmoidoscope or refer to images of your colon on a monitor. If anything suspicious is found, your physician may take a tissue sample (a biopsy) for further testing.

CT Colonography

This test is also known as a virtual colonoscopy. Computer software is used along with a CT scan to examine the colon for polyps. A thin tube is placed in the rectum and the colon is filled with air, followed by the CT scan of the colon and rectum.

Although this test is less invasive than a colonoscopy, it still requires a colon cleansing. Many patients experience uncomfortable cramping as a result of air being pumped into the colon. If polyps or other suspicious areas are found, a colonoscopy will probably still be needed.

Double-Contrast Barium Enema

A barium liquid is put into the rectum by way of the anus. Barium is a metallic compound that helps images of the lower gastrointestinal tract, including polyps and tumors, show up on an x-ray.

Digital Rectal Exam (DRE)

Using a gloved, lubricated finger the doctor examines the rectum to check for lumps or other abnormalities. If anything suspicious is found, additional testing may be needed. DRE is often part of a routine physical exam.

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Risks and Symptoms



Treatment Options