What are the signs of colon cancer?

Lata C. Thatai, MD
Hematology & Oncology
Alteration of bowel movements, blood, chronic abdominal pain, anemia and other issues can be signs of colon cancer. In this video, Lata C. Thatai, MD from Parkland Medical Center, goes into details about the condition.
There are no early signs for colon cancer; signs only appear in later stage colon cancer. Watch John Rioux, MD, of Fawcett Memorial Hospital, discuss the importance of early screening.
Colon cancer can have many different warning signs; early cancer usually doesn't not have any signs or symptoms, but things that should make you more concerned and be evaluated by a physician include noticing blood or a dark color with your bowel movements, persistent changes in the character of your bowel movements (e.g., diarrhea or constipation), cramping, gas, bloating, a feeling like there's still stool in your intestines despite just completing a bowel movement, weakness, fatigue or weight loss.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
If caught early, colon cancer is one of the most curable cancers, which is why it’s important to know the warning signs. While polyps detected during colonoscopies are a risk factor, bloating can be a symptom. Bloating related to colon cancer is caused when the tumor blocks the colon, preventing gases and feces from moving through.

Other symptoms related to colon cancer include bloody stools, a change in the shape of your stool and the feeling you urgently have to urinate.

Starting at age 50, you need to have a colonoscopy every 10 years. If you have a parent or sibling with a history of colon cancer, start getting your colonoscopy 10 years before they were diagnosed.
Symptoms of colon cancer develop late in disease, which is why we screen patients at regular intervals rather than waiting for symptoms. Weight loss, change in bowel habits, unexplained abdominal pain, anemia, rectal bleeding, occult blood in the stool, or bowel obstruction can be signs of colon cancer.
A common symptom of colorectal cancer is a change in bowel habits. Symptoms include:
  • Having diarrhea or constipation
  • Feeling that your bowel does not empty completely
  • Finding blood (either bright red or very dark) in your stool
  • Finding your stools are narrower than usual
  • Frequently having gas pains or cramps, or feeling full or bloated
  • Losing weight with no known reason
  • Feeling very tired all the time
  • Having nausea or vomiting
Most often, these symptoms are not due to cancer. Other health problems can cause the same symptoms. Anyone with these symptoms should see a doctor to be diagnosed and treated as early as possible.

Usually, early cancer does not cause pain. It is important not to wait to feel pain before seeing a doctor.

This answer is based on source information from the National Cancer Institute.

Continue Learning about Colon Cancer

Colon Cancer

Caused by growths that turn malignant, colon cancer develops slowly over several years.The cancer begins when precancerous growths called adenomatous polyps form in the tissues of the colon, which makes up the lower part of our di...

gestive system. Polyps can be detected through colon screenings. A colonoscopy uses a thin, lighted tube to search for polyps, cancer and abnormal areas in the colon and rectum. A colonoscopy is recommended at least every 10 years, starting at the age of 45 for African-Americans who are at greater risk for the cancer and at 50 for other races. Your risk for colon cancer increases if you have had previous cancers, a family history of colon or rectal cancers, or have ulcerative colitis. See your doctor if you have rectal bleeding, notice changes in your bowel movements or have unexplained weight loss. To prevent colon cancer, get screened as recommended by your doctor, maintain a healthy diet, exercise often and quit smoking if you currently do.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.