What are the symptoms of colon cancer?

Joseph Stilwill, MD
Hematology & Oncology
Blood in the stools or abdominal pain can be symptoms of colorectal cancer. Unfortunately, colorectal cancer in its early stages often has no symptoms. This is why screening is essential.
Rosendo I. Collazo, DO
Internal Medicine
The signs and symptoms of colon cancer include:
  • a change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days
  • a feeling that you need to have a bowel movement that is not relieved by doing so
  • rectal bleeding
  • blood in the stool
  • cramping or abdominal (belly) pain
  • weakness and fatigue
  • unintended weight loss
Most of the time, there are no symptoms, which makes primary, proactive screening so essential. People need to talk to their doctor if they experience these symptoms. Seeking medical treatment makes a huge difference in people's outcomes.
There are no specific signs and symptoms of colon cancer, says Joseph Thornton, MD, a colorectal surgeon at Sunrise Hospital. In this video, he says that blood in the stool can be a sign, but often it isn't visible. 
Stephanie A. Wishnev, MD
Colorectal Surgery
There are no early symptoms of colon cancer, says Stephanie Wishnev, MD, a colorectal surgeon at MountainView Hospital. In this video, she says bleeding and a change in bowel habits may come later, which is why screening is important. 
Both benign colon polyps and malignant colon polyps may cause few or no symptoms. When colon cancer does cause symptoms, these symptoms may take the form of diarrhea, constipation, or narrowing of the stool as the tumor begins to interfere with bowel function. Typically, these symptoms would last for more than a few days. A tumor in the colon may also cause people to feel like they have to go, and the sensation is not relieved by a movement. Bleeding or blood in the stool and abdominal pain or cramping may also be signs of colon cancer.

However, all of the previously mentioned symptoms can also be the result of far less dangerous health problems, such as hemorrhoids or irritable bowel syndrome, so having these symptoms does not mean that a person has colon cancer. In fact, these symptoms are more likely to be due to a condition other than colon cancer.
Lisa Ganjhu, DO
The tricky thing about colon cancer is that doesn’t have a lot of obvious early-warning symptoms. Check out this video with gastroenterologist Dr. Lisa Ganjhu to learn the small and subtle cues you can clue into.
Deborah M. Axelrod, MD
Surgical Oncology
Colon cancer is highly treatable when found early, so it's important to know the symptoms so you can get them checked right away. In this video, cancer specialist Deborah Axelrod, M.D., discusses the colon cancer symptoms you should never ignore.
David Greenwald, MD
Colorectal cancer is often present in people without symptoms, making prevention and screening for colorectal cancer very important. A polyp may be found and removed even before it becomes cancerous or presents with symptoms; once symptoms appear, a colonoscopy is performed to aid in diagnosis, rather than screen for disease.

The following signs or symptoms, however, might indicate colorectal cancer:
  • blood in stools
  • narrower than normal stools
  • unexplained abdominal pain
  • unexplained change in bowel habits
  • unexplained anemia
  • unexplained weight loss
These symptoms may be caused by other benign diseases such as hemorrhoids, inflammation in the colon or irritable bowel syndrome. The presence of these symptoms for more than a few days is an indication to talk with a gastrointestinal specialist about these symptoms and the patient’s family history.

Colon cancer symptoms often center around the colon and digestive system. Rectal bleeding or bloody bowels for a few weeks are common. A person may also feel gassy or have painful cramps, and may feel like they cannot empty their bowel completely. They may also feel tired or weak and lose weight. In the early stages, colon cancer may present no symptoms.

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.