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Colon Cancer: Know the Warning Signs

20 de marzo de 2026
Happy elderly couple holding hands walking in park.

No one likes to talk about colon cancer. And that’s OK, as long as you take steps to protect yourself. After all, colon cancer is the second leading cause of cancer deaths in the United States. And, nearly one half (45%) of new colon cancer diagnoses are currently in individuals younger than 65. 

A good place to start taking action is by getting a preventive screening.

Talk with your doctor about when you should be screened and how often. Your age and family history will play a role in deciding what's best for you.

Why Is Screening Important?

Small growths, called polyps, can grow along the colon lining. Some of these polyps can be cancerous or become cancerous if left untreated. A colonoscopy can help find these growths and possible cancers early. Early detection offers a better chance for successful treatment and recovery.

Are There Warning Signs?

Before it has grown or spread, colon cancer often doesn't have any symptoms. There may be warning signs, though. Pay attention if you notice any:

  • Change in bowel habits or stool shape that lasts more than a few days and isn’t caused by a change in diet
  • Cramping or stomach pain
  • Pérdida de peso inexplicable
  • Fatigue, shortness of breath or weakness due to anemia
  • Rectal bleeding
  • Blood in the stool or toilet after a bowel movement
  • Heces oscuras o negras
  • An urge to go even though the bowel is empty

Your doctor may recommend a colon screening if you have one or more symptoms.

When and How Should I Be Screened?

While the U.S. Preventive Services Task Force (USPSTF) recommends adults 45-75 be screened, talk about the risks and benefits with your health care provider. Ask when and how often you should be screened.*

If you have a family history of colon cancer or other health issues that put you at higher risk, your doctor may advise earlier or more frequent screening.

Today, there are simple noninvasive screening choices, too. Talk to your health care provider (doctor, nurse practitioner, physician assistant, etc.) about which ones may be right for you. Each has advantages and disadvantages. The test you and your health care provider choose may depend on your preferences and medical condition.

The most common screening option is colonoscopy. Using a flexible, lighted tube equipped with a small camera, your doctor can look at the whole rectum and colon for signs of cancer. Precancerous polyps may even be removed during the test.

Some people avoid a colonoscopy because they worry it might be painful. Pero el examen es rápido e indoloro. You are asleep during the test, and it takes less than an hour.

Other screening options include:

Fecal occult blood test: This lab test scans a stool sample for blood, a possible sign of cancer. Fecal immunochemical testing (FIT) uses antibodies to spot blood in the stool. Fecal immunochemical testing (FIT)-DNA combines FIT with a test that finds changes in the DNA of stool.

Sigmoidoscopy: This method looks only at the rectum and the lower colon.

Virtual colonoscopy: A CT scan gives detailed images of the colon.

Are There Ways to Prevent Colon Cancer?

While there is no sure way to stop colon cancer from developing, you can take steps to help lower your risk.

  • Ingiera una dieta rica en frutas, verduras y fibra.
  • No consuma carne roja, asada ni procesada.
  • Avoid smoking, heavy use of alcohol and inactive lifestyles.
  • Ejercicios
  • Mantenga un peso saludable.

Learn more about colon cancer and other recommended health screenings in our Recomendaciones de bienestar para adultos. As always, check to make sure your care and testing providers are in network. Show your insurance ID card so providers can check if they are part of your health plan network.

For details about your benefits coverage, log in to your member account online.

* Las recomendaciones pueden variar. Hable sobre las opciones de exámenes con su prestador de servicios médicos, especialmente si tiene un mayor riesgo.

Fuentes: Colorectal Cancer Statistics, 2026, American Cancer Society, 2026; Cáncer Colorrectal, U.S. Centers for Disease Control and Prevention, 2025; Examen de cáncer colorrectal (el contenido de este enlace solo está disponible en inglés), U.S. Preventive Services Task Force 2021; Cáncer de colon Mayo Clinic, 2024; Colon Cancer (Colorectal Cancer) Cleveland Clinic, 2025