Colon cancer - Signs & Symptoms

Usually there are no signs or symptoms of colon cancer until it is too late. Because of this it’s important that you have regular colon screenings to detect potential problems before they become life threatening.

One of the earliest symptoms may be bleeding. The amount of blood will probably be too small to detect with the naked eye and require the use of chemical testing of your stool. Once the tumor grows larger, other symptoms may develop such as:

A change in your bowel habits. This includes changes such as constipation and diarrhea.
Narrow stools. The stool can become narrow or even pencil-thin in caliber.
Visible blood in the stool. Cancer low in the colon, near or in the rectum, can produce blood that is bright red in color. When the cancer is higher up in the colon it will typically turn the stool black and tarry.
Anemia. Because of blood loss you can become anemic and feel tired and sluggish.
Stomach or gas pain.
Weight loss.

Blood can also indicate other problems besides cancer. For example, hemorrhoids, a tear in your anus, polyps, and other conditions can result in blood. Iron supplements also turn your stools black.

So, while none of these symptoms absolutely mean you have cancer, you should tell your doctor if any of these symptoms persists.