8 Things to Know About Colorectal Cancer Screenings
Rates decreasing in older adults, increasing in younger
Rates decreasing in older adults, increasing in younger
Key Takeaways
- Screening can help prevent colorectal cancer.
- Most adults should start screening at age 45.
- Colonoscopy remains the gold standard test.
- Cases are increasing in adults younger than 50.
Colorectal cancer is one of the most preventable cancers and one of the most successfully treated when detected early.
Screenings allow a doctor to identify precancerous polyps (growths) and remove them before they become cancerous. Yet many people delay screening because they don’t know when to start or which test is right for them.
While rates of colorectal cancer have declined in older adults, cases are rising in younger adults, making awareness and early detection more important than ever.
“When colorectal cancer is diagnosed at earlier stages, treatment options are more successful,” says Walter Coyle, MD, a gastroenterologist at Scripps Cancer Center and Scripps Clinic. “That is why it’s important when the time comes to talk to your doctor about when and how you should be screened for colon cancer.”
What is colorectal cancer?
Colorectal cancer includes both colon cancer and rectal cancer, depending on where the disease begins. Most colorectal cancers start as abnormal growths called polyps in the colon or rectum. Over time, some polyps can become cancerous.
Because polyps often grow slowly, sometimes over 10 years, screening can help find and remove them before cancer develops.
Eight things to know about colon cancer screening
1. Colorectal cancer is one of the common cancers in the U.S.
The American Cancer Society estimates nearly 160,000 people will be diagnosed with colorectal cancer this year.
Colorectal cancer is also a leading cause of cancer deaths in both men and women. It is expected to cause more than 55,000 deaths this year.
2. Colorectal cancer develops slowly, with few early signs or symptoms
Colorectal cancer almost always starts with an abnormal growth known as a polyp in the colon or rectum. Not all polyps are malignant. A polyp, however, can take as many as 10 years to develop into cancer. This is why there are generally few symptoms during the early stages of the disease.
Warning signs can include:
- Blood in the stool or rectal bleeding
- Persistent abdominal pain or cramping
- Changes in bowel habits, including diarrhea or constipation
- Narrowing of the stool
- Unexplained weight loss or fatigue
“Other conditions may also cause these symptoms, so it is important to identify the cause and get treatment,” Dr. Coyle says.
3. Screening can prevent colorectal cancer
Screening doesn’t just detect cancer. It can help prevent it.
Many colorectal screening tests can detect precancerous polyps before they become cancerous. When colorectal cancer is found early, the five-year survival rate is about 90%. However, only about 4 in 10 colorectal cancers are diagnosed at an early stage.
4. Most adults should begin screening at age 45
The U.S. Preventive Services Task Force and the American Cancer Society recommend colorectal cancer screening beginning at age 45 for adults of average risk. People with certain risk factors may need earlier screening.
“If you have a family history of colorectal cancer or risk factors, such as inflammatory bowel disease, your doctor may recommend having your first screening at a younger age,” Dr. Coyle says.
5. Colorectal cancer cases are increasing among younger adults
Colorectal cancer rates have steadily declined among adults over 50, largely because more people are getting screened. However, cases among adults younger than 50 have increased since the 1990s, according to the American Cancer Society. Colorectal cancer currently is the most common cancer-related death in people under 50.
Doctors encourage younger adults to pay attention to symptoms such as:
- Rectal bleeding
- Abdominal pain
- Changes in bowel habits
- Unexplained fatigue
6. Colonoscopy remains gold standard for screening
Colonoscopy is considered the most effective colorectal cancer screening test because it allows doctors to detect and remove polyps during the same procedure.
During a colonoscopy, a doctor inserts a flexible tube with a small camera into the rectum to examine the entire colon. Patients are sedated for comfort. If precancerous polyps are found, they can often be removed during the procedure.
For most people at average risk, colonoscopy is recommended every 10 years.
7. Other screening tests are also available
Several noninvasive screening options are available for people who cannot or do not want to undergo a colonoscopy.
FIT stool-based test: A fecal immunochemical test (FIT) checks for hidden blood in the stool, which can be a sign of colorectal cancer. No bowel prep is needed. While effective, FIT testing is less effective than colonoscopy at detecting precancerous polyps.
The test is typically performed once a year. If results are positive, a follow-up colonoscopy is recommended.
Cologuard stool DNA test: This at-home stool test checks for abnormal DNA and hidden blood in stool samples. It is more sensitive than the FIT test for detecting cancer but has higher false-positive rates. The test is typically recommended every three years for adults at average risk. A positive result should be followed by a colonoscopy.
Blood-based screening test: In 2024, the FDA approved a blood test called Shield by Guardant for colorectal cancer screening for adults 45 years and older who are at average risk. The test detects abnormal DNA in the blood associated with colorectal cancer.
Although it is less effective than colonoscopy at detecting precancerous polyps, experts believe blood-based screening may encourage more people to participate in colorectal cancer screening, especially those reluctant to complete stool-based or visual screening tests.
8. Lifestyle changes can help lower your risk
Several lifestyle factors linked to colorectal cancer can be modified.
To help reduce your risk:
- Maintain a healthy weight
- Exercise regularly
- Limit red and processed meats
- Eat a diet rich in fruits, vegetables and whole grains
- Avoid smoking
- Limit alcohol consumption
Some studies suggest Vitamin D (especially for women) and regular consumption of coffee may be associated with a lower risk of colorectal cancer, though more research is needed.
Cancer care at Scripps
Cancer specialists at Scripps provide comprehensive care for nearly all types of adult cancer, including colorectal cancer. Multidisciplinary teams guide patients through every stage of care — from diagnosis and staging to treatment and supportive services — with personalized plans tailored to each patient’s needs.