Colorectal cancer is one of the most common types of cancer, but the good news is it can often be prevented or successfully treated if found early. The way to find it is with regular screening.

When should I get screened?

Colorectal cancer may not cause symptoms at first, so getting screened is very important. Screening can help find cancer early, before it spreads, which makes it easier to treat. Many tests can also find small growths called polyps, which doctors can remove before they turn into cancer.

The US Preventive Services Task Force recommends that adults ages 45 to 75 get regular screenings for colon cancer. How often you need screening depends on your health, family history and the type of test you and your doctor choose.¹

If you are over 75, talk with your doctor to determine if you need screenings based on your health history.

Types of colorectal cancer screening

There are different ways to check for colorectal cancer. Some tests can be done at home, while others need to be done by a doctor. Home tests look for small amounts of blood or DNA changes in your stool that could be signs of cancer. Other tests let doctors look inside your colon for unusual growths. Your doctor will recommend the best test for you. Here are the options.^1,2

Screening at home

• Fecal Immunochemical Test (FIT) (Every year): This test checks for blood in your stool, which can be a sign of cancer or polyps. It’s about 80% accurate at finding cancer.³
• Stool DNA Test (Every 1 to 3 years): This test checks for blood and DNA changes linked to cancer. It’s the most accurate home test, finding 92% of cancers.³

Screening by a health care provider

• Blood Tests: These are a newer way to check for colorectal cancer, but it isn’t known yet how often people should get them. Blood tests look for signs of cancer in your blood, but they can’t diagnose cancer on their own.
• Colonoscopy (Every 10 years): This is one of the most complete ways to check for colorectal cancer. A doctor uses a small camera on a flexible tube to look inside your colon. If they find polyps (small growths), they can remove them during the test to help prevent cancer.
• CT Colonography (Virtual Colonoscopy) (Every 5 years): This is a special scan that takes pictures of your colon to check for polyps or cancer. It’s a good option for people who can’t or don’t want to have a colonoscopy.
• Sigmoidoscopy (Every 5 years): This test is like a colonoscopy but only looks at part of the colon.

If you have a test other than a colonoscopy and the results are abnormal, your doctor will probably suggest you get a colonoscopy to check further.

What are the symptoms of colorectal cancer?

Colorectal cancer doesn’t always cause noticeable symptoms in its early stages. That’s why screening is so important. However, as the cancer grows, you may experience:⁴

• Changes in your bowel habits (diarrhea or constipation)
• Blood in your stool (bright red or dark stools)
• Unexplained weight loss
• Stomach pain or cramping
• Feeling like you still need to go to the bathroom after having a bowel movement
• Fatigue or weakness

If you notice any of these symptoms, talk to your doctor as soon as possible.

Treatment options for colorectal cancer

If you find out you have colorectal cancer, your treatment will depend on how much the cancer has spread, your overall health and what you prefer. The main ways to treat it include:⁵

• Surgery is often the first step in treating colorectal cancer. A doctor will remove polyps with cancer or sections of the colon or rectum that have cancer.
• Chemotherapy uses drugs to kill cancer cells and shrink tumors.
• Radiation therapy uses high-energy X-rays to kill or keep cancer cells from growing.
• Targeted therapy attacks specific cancer cells without harming healthy ones.
• Immunotherapy helps your immune system fight cancer.

Metastatic colorectal cancer: What happens when cancer spreads?

When colorectal cancer spreads to other parts of the body, it is called metastatic colorectal cancer. The most common places it spreads to are the liver, lungs, or lymph nodes. Your doctor may suggest using more than one treatment at the same time, depending on what treatments you’ve had and where the cancer has spread.⁶

Colorectal cancer myths

There are many misunderstandings about colorectal cancer, including what causes it. Here are some common questions people ask:

• Can Listerine cause colorectal cancer? No, there is no scientific proof that Listerine or other mouthwashes with alcohol cause colorectal cancer. If you’re worried, you can use an alcohol-free mouthwash.^7,8
• Can a dental infection cause colorectal cancer? One dental infection won’t cause cancer, but some studies suggest a link between oral health and colorectal cancer. However, scientists need more research to understand this connection.⁹
• Does thin stool mean you have colon cancer? Thin or narrow stools can happen for many reasons, like changes in your diet or minor digestive problems. If your stool stays thin for a long time, you should see a doctor, but it doesn’t always mean you have colon cancer.¹⁰

Colorectal cancer is common, but finding it early means it will be easier to treat. Home tests, colonoscopies, and other screenings can help find cancer before you feel sick. Don’t skip your screening because you’re scared or too busy — it’s not worth the risk. Talk to your doctor about the best test for you and get it done. It could save your life.

References:

1. Centers for Disease Control and Prevention. Colorectal cancer screening. https://www.cdc.gov/colorectal-cancer/screening/index.html
2. American Cancer Society. Colorectal cancer screening tests. https://www.cancer.org/cancer/types/colon-rectal-cancer/detection-diagnosis-staging/screening-tests-used.html
3. Home screening options for colorectal cancer. Harvard Health. (2022).https://www.health.harvard.edu/cancer/home-screening-options-for-colorectal-cancer
4. Centers for Disease Control and Prevention. (2024). Symptoms of colorectal cancer. https://www.cdc.gov/colorectal-cancer/symptoms/index.htmlhttps://www.health.harvard.edu/cancer/home-screening-options-for-colorectal-cancer
5. National Cancer Institute. Colon cancer treatment – Patient version.. https://www.cancer.gov/types/colorectal/patient/colon-treatment-pdq
6. Treatment of metastatic colorectal cancer: ASCO guideline. (2023). Journal of Clinical Oncology. https://doi.org/10.1200/JCO.22.01690
7. The effect of daily usage of Listerine Cool Mint mouthwash on the oropharyngeal microbiome: A substudy of the PReGo trial. (2024). Journal of Medical Microbiology. https://doi.org/10.1099/jmm.0.001830
8. Mouthwash with alcohol and oral carcinogenesis: Systematic review and meta-analysis. (2020). Journal of Evidence Based Dental Practice. https://doi.org/10.1016/j.jebdp.2020.101407
9. Insights into oral microbiome and colorectal cancer – On the way of searching new perspectives. (2023). Frontiers in Cellular and Infection Microbiology. https://doi.org/10.3389/fcimb.2023.1159822
10. “Low caliber stool” and “pencil thin stool” are not signs of colorectal cancer. (2009). Digestive Diseases and Sciences. https://doi.org/10.1007/s10620-008-0356-1