Colon Cancer Symptoms You Can’t Afford to Ignore

If you notice these colon cancer signs, see a doc ASAP.

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The most common symptom of colon cancer? “Nothing,” says Anthony Starpoli, MD, a gastroenterologist in New York City.

Colon cancer a growth of abnormal cells that occurs in the lining of the colon or rectum. This growth eats away at the normal cells, and converts them or replaces them with cancerous cells.


The Signs and Symptoms of Colon Cancer

Colon cancer often shows no symptoms because tumors can easily “hide” in the colon. “The colon holds stool; it holds debris. It can hold a tumor until you can recognize that it’s there, by way of pain or having bleeding. And at that point, you have an advanced lesion,” says Dr. Starpoli.

Colon cancer is routinely screened by colonoscopy and other procedures, but if you’re younger than the recommended screening age and notice potential colon cancer symptoms, it’s important to get them checked out. Cases of colon cancer among young adults are on the rise, research shows. According to a study published in the Journal of the National Cancer Institute, people born in 1990 have double the colon cancer risk and quadruple the rectal cancer risk compared to people born around 1950, when risk was lowest.

These concerning colon cancer symptoms include:

  • A change in bowel habits—like diarrhea, constipation, or pencil-like stool—that lasts for more than a few days
  • The urge to have a bowel movement that isn’t relieved by doing so
  • Rectal bleeding
  • Dark stools, or blood in the stool
  • Cramping or abdominal (belly) pain
  • Weakness and fatigue
  • Unintended weight loss

Here’s more about what the color of your bowel movements can reveal about your health.

The Key to Preventing Colon Cancer

“Colon cancer can most definitely be caught early—and really, it’s all about prevention,” says Starpoli. The American Cancer Association recommends regular screenings starting at age 50 for people at average risk of colon cancer. Those with an increased risk because of family history or other factors should get screened sooner. (Here are more crucial tests women need in their 50s.) Getting your stools checked for hidden blood as part of a physical exam should start annually by age 40, says Dr. Starpoli.

During a screening—usually a colonoscopy—doctors insert a camera into the colon to identify pre-cancerous growths, or polyps. These polyps, which can be as small as a seed or the size of a tennis ball, can be removed during the procedure, which can then prevent colon cancer from developing. “The process is quite unique in the fact that diagnosis and therapy is given in that same session,” says Dr. Starpoli.

“People need to understand that there is no one symptom for colon cancer. If you have symptoms of a cancer of the colon, you’re probably dealing with a more advanced situation. That’s why we recommend screening early, whether it be stool testing, colonoscopy, or some imaging like visual colonoscopy,” says Dr. Starpoli.