Rectal Cancer Screening

What is rectal cancer screening?

Rectal cancer screening detects signs of cancer in the rectum. Rectal cancer doesn’t always cause symptoms in its early stages, so screenings are important to catch the condition as soon as possible.

If your screening shows signs of rectal cancer, you’ll have additional testing to help diagnose the condition. When found early, rectal cancer is considered very treatable.

Rectal cancer screening guidelines

For people with an average risk, the rectal cancer screening guidelines from the U.S. Preventive Services Task Force recommend starting routine colorectal screenings at 45 years old. This age was previously 50, but the guidelines lowered the age to 45 in 2021, partly due to an increase in colorectal cancer in younger adults.

The guidelines include several types of screening options, from stool tests to exams that look inside your rectum and colon. It’s important to talk with your doctor about the benefits of each option and the right choice for you. If you have any risk factors for rectal cancer, you should also talk with your healthcare provider about starting screening sooner than age 45. You may need a specific type of screening based on your risk.

Compare screening guidelines for average and higher-risk people:

Screening for average-risk people

If you don’t have any factors that put you at a higher risk for rectal cancer, you should have routine screenings between the ages of 45 and 75. If you’re 76 to 85, discuss the benefits or risks of continuing screenings with your doctor.

Your doctor can also guide you through the different colorectal screening options and help you choose one that fits your needs.
Screening for higher-risk people
People with risk factors for rectal cancer should ask their healthcare team about their specific screening needs. Often, your doctor will recommend you start rectal cancer screenings sooner, have them more frequently or use a specific test like a colonoscopy.

Screening in those with a high risk is based on several factors, so talk to your doctor if you have any of the following risk factors for rectal cancer:
- Colorectal polyps: If you have a personal history of colorectal polyps, you’ll likely need a screening colonoscopy more often—such as every three years.
- Colon or rectal cancer: If you’ve had colorectal cancer before, you may have follow-up imaging tests or start surveillance a year after surgery.
- Family history: Depending on your colon or rectal cancer family history, your doctor could recommend starting screening earlier than 45.
- Inflammatory bowel disease: If you’ve been diagnosed with inflammatory bowel disease, including ulcerative colitis or Crohn’s disease, you may need a colonoscopy screening every one to three years, depending on how long you have experienced symptoms of the disease.
- Genetic syndromes: People who have conditions like Lynch syndrome or familial adenomatous polyposis need colonoscopies at more frequent intervals and should start screening at an early age.

Better understand your options—rectal cancer screening tests

The first step to protecting yourself from rectal cancer is understanding your screening options. Some people hesitate to get screened for colorectal cancer because they don’t realize they have choices. Knowing the benefits of each type of test and what to expect can help put your mind at ease.

Colonoscopy is one of the most known and recommended rectal cancer screening tests. It can detect rectal cancer and remove rectal polyps before they become cancer. However, any screening for rectal cancer is better than no screening. Talk with your doctor and plan to get screened with an option that works for you.

If you choose a screening other than colonoscopy, it’s important to know that a diagnostic colonoscopy usually follows up on any abnormal screening results found during another test.

Colonoscopy

During a colonoscopy, your doctor guides a thin tube with a light and a camera through the colon and rectum to look for polyps or signs of cancer. This procedure allows your doctor to remove polyps or take tissue samples when extra testing is needed.

This test requires bowel prep ahead of time to clean out your colon and uses general anesthesia so that you are asleep during the procedure. If you don’t have any risk factors for colorectal cancer, it’s recommended that you get a colonoscopy every ten years.

Double contrast barium enema (DCBE)

A double contrast barium enema is an imaging test sometimes used to look for polyps or cancer in the rectum. It uses X-rays to create images of the colon and rectum. During this test, the radiology technician injects barium into the rectum to coat it, which makes the colon and rectum more visible on the X-ray.

Sigmoidoscopy

A sigmoidoscopy lets your doctor look at the inside of your rectum and the bottom portion of your colon. During a flexible sigmoidoscopy, a thin tube with a camera and a light is guided through the intestinal tract, much like a colonoscopy.

Sigmoidoscopy only looks at the bottom portion of the colon. As a result, it isn’t a common choice for colorectal screening. If you choose this test, you’ll need to do an enema bowel prep beforehand. Frequently, it is used as a screening tool for individuals who have undergone a prior operation that removed almost all sections of the colon.

Stool tests

Stool tests for rectal cancer let you collect samples of your stool from the comfort of your home and send them to the lab to detect signs of cancer. A few stool tests for colorectal cancer look for blood, DNA or both in the stool. These tests have limited capacities, including the possibility of a false positive or a missed polyp or tumor. Talk with your doctor to understand the benefits and drawbacks of stool tests.

Guaiac-based fecal occult blood test (gFOBT): A fecal occult blood test looks for hidden blood in the stool, which could be a sign of rectal cancer or other digestive conditions. This test is recommended every year as a screening for colorectal cancer. Before taking stool samples, your doctor may ask you to limit certain foods, like red meats, or stop taking certain medications, especially iron.
Fecal immunochemical test (FIT): A FIT test looks for signs of blood in the stool to help detect colorectal cancer. You’ll receive a kit to collect multiple samples at home, and you typically don’t need to change your diet or medications before the test. For screening, FIT is recommended every three years.
Stool DNA test: A stool DNA test looks for hidden blood in the stool and DNA pieces that might indicate the presence of polyps or cancer. This type of stool test doesn’t require diet or medication changes, and it’s recommended every three years.

Virtual colonoscopy

You may choose to have a virtual colonoscopy every five years to screen for rectal cancer. This exam uses CT imaging while you are awake to provide images of the colon and rectum and look for signs of cancer. Like a colonoscopy, a virtual colonoscopy requires bowel prep ahead of time to clean out the intestinal tract and provide a clear view of your colon and rectum. If a lesion is identified on the CT scan, a colonoscopy will be necessary to biopsy or remove the tissue.

Frequently asked questions

How is rectal cancer diagnosed?

Rectal cancer is diagnosed via colonoscopy, where a camera-equipped tube is inserted through the rectum. During this procedure, your doctor can take tissue samples for lab testing. Rectal cancer can be discovered during routine screenings or while investigating digestive issues.
Can a CT scan detect rectal cancer?

Yes. A virtual colonoscopy, a specific type of CT scan, can detect signs of rectal cancer or polyps. CT imaging may also be used to see if cancer has spread to other body parts, such as the pelvis, chest or abdomen. However, a colonoscopic biopsy is needed to confirm a cancer diagnosis.
Can blood tests detect rectal cancer?

Not exactly. Blood tests may be able to detect a specific protein in the blood, called CEA, that could be a sign of rectal cancer. However, a blood test alone isn’t enough to diagnose rectal cancer, and blood tests aren’t currently recommended as a primary screening option.
How is rectal cancer detected early?

The best way to detect rectal cancer early is to follow your doctor’s guidance on routine colorectal screenings. A colonoscopy remains the most recommended test to check for signs of early rectal cancer, remove pre-cancerous polyps and give you peace of mind.
Does a colonoscopy detect rectal cancer?

Yes. A colonoscopy allows your doctor to visualize the lining of your entire rectum and colon while looking for signs of rectal cancer. It’s considered one of the most sensitive screening tests for the condition, and your doctor can take tissue samples for additional testing in the lab.

What is rectal cancer screening?

Why is rectal cancer screening so important?

Rectal cancer screening guidelines