Signs and Symptoms of Colon Cancer

By Katharine Paljug @kpaljug
October 08, 2021
08 Nov 2014 --- Portrait of mature man sitting alone on stairway --- Image by © Steve Prezant/Corbis

Signs and symptoms of colon cancer can often be mistaken for other gastrointestinal conditions, so it is important to talk with your doctor about any changes you notice.

Colon cancer, or cancer that first develops in the large intestine, is a form of colorectal cancer. It is the second deadliest cancer for adult men and women, according to the National Cancer Institute. Colon cancer affects 41 out of every 100,000 adults, and in 15 of those cases, it is fatal.

Some groups of people, such as those with a family history of colorectal cancer or those with inflammatory gastrointestinal diseases like Crohn’s disease, have an increased risk for developing colon cancer. But even without a risky medical history, anyone can develop colon cancer, most often between ages 45 and 75, but people younger than 45 are increasingly being diagnosed with colon cancer.

Because colon cancer becomes more dangerous the longer it goes untreated, it is important to know what symptoms to watch for and bring to your doctor’s attention.


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Signs and symptoms of colon cancer

Symptoms of colon cancer, according to the American Cancer Society, often first appear in the gastrointestinal system.

Watch for changes in bowel habits that last for more than a few days, such as diarrhea, constipation, or stools that are much thinner than normal. You may also notice a feeling that you need to have a bowel movement but not feel any relief after you do.

Other signs of colon cancer include dark or bloody stools, rectal bleeding that occurs over several days, unexplained weight loss, extreme fatigue or exhaustion, and cramping, bloating, or pain in your belly. You may experience one, two, or all of these signs at once, or several over the course of a few weeks or months.

However, the American Cancer Society stresses that each of these signs can also indicate many other disorders, such as hemorrhoids, anal fissures, infection, irritable bowel syndrome, ulcerative colitis, or inflammatory bowel disease. The only way to know for sure whether your symptoms are caused by cancer or another condition is to speak with a doctor about how you have been feeling.

Why you shouldn’t wait for symptoms of colon cancer

Though colorectal cancer can cause noticeable symptoms, many times these do not appear until much later in the progression of the disease.

The very first symptom of colon cancer is the development of tumors or precancerous polyps in the colon, often with no other noticeable sign that anything is wrong. Other symptoms generally develop after the cancer has grown and spread, becoming more dangerous.

Because the initial stages of the disease are so difficult to detect, the Centers for Disease Control and Prevention recommend that all adults undergo testing for tumors or polyps in the colon. The best way to do this is by receiving regular colonoscopy screenings.

A colonoscopy will allow your doctor to find and remove any dangerous growths before they spread and begin more severe symptoms. Most men and women can start these tests at age 45, though those with a high risk profile may need to begin screening earlier.

Talking to your doctor about colon cancer symptoms

Because there is so much overlap in symptoms for any gastrointestinal condition, it can be hard to distinguish whether the changes you notice are a sign of colon cancer or something else. It is easy to become either too alarmed, assuming that every change in bowel habits indicates that you have cancer, or not alarmed enough, missing warning signs because you attribute them to temporary digestive distress.

To avoid either over- or underreacting, pay attention to any changes in your bowel habits or energy levels. If they persist for more than a couple days, talk to your doctor. A medical professional will be able to assess your symptoms, examine you, and decide whether colon cancer screening or another treatment needs to be done.


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October 08, 2021

Reviewed By:  

Christopher Nystuen, MD, MBA