Colon cancer is the most common digestive cancer and can often have few symptoms for quite some time until the disease is extensive. For this reason it is important to recognize the early warning symptoms of colon cancer and why many physicians recommend periodic screening tests and exams to catch the disease as early as possible.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Colon Cancer and Back Pain

Colon cancer causes few symptoms in its early stages, and back pain is an uncommon symptom. Back pain and colon cancer aren't necessarily correlating concepts; the colon is a hollow organ with muscular, somewhat-elastic walls, masses such as tumors cause few symptoms until they are quite large and advanced. Also, because the contents of the colon are very liquid-based, with water being absorbed as feces pass slowly through the length of the colon, changes in bowel habits due to obstruction do not occur until colon tumors are quite large.

Possible Symptoms of Colon Cancer: Occult Bleeding

Bleeding in the colon is a leading warning symptom of colon cancer. Blood loss that is obvious and bright red, however, is not a typical finding of colon cancer. Bright red blood, such as visible streaks on the stool and on toilet paper usually signifies bleeding very close to the outside of the body, such as a bleeding hemorrhoid or blood loss from an anal fissure, though it nonetheless requires evaluation by a doctor. Blood loss that is a sign of colon cancer is usually "occult," meaning that it is hidden inside the stool and not obvious. Stool samples may be tested with chemicals that can identify the presence of blood in the feces. Such a test is often a routine screening test done during physical exams to assess the presence of occult blood.

Possible Symptoms of Colon Cancer: Fatigue and Anemia

Since tumors cause few symptoms themselves, signs and symptoms from chronic blood loss can be the first symptom to arise. Chronic blood loss, even in very small amounts, can lead to anemia, which is a warning sign of colon cancer. The body is unable to make red blood cells as fast as it is losing them, and a low red blood cell count -- referred to as anemia, results.

Red blood cells carry oxygen throughout the body. When there's a lack of normal red blood cell numbers, the oxygen-carrying capacity reduces and can result in fatigue, an inability to exert oneself and light-headedness. When a routine blood test reveals anemia, a physician will search for a cause of that anemia, including testing for occult blood in the stool to rule out colon cancer.

Can Colon Cancer Cause Back Pain?

As explained, "back pain" is not a typical or early sign of colon cancer, but can occur with advanced disease as the tumors begin to obstruct the passageway through the colon. The colon has a strong muscle in its wall that contracts in a coordinated wave-like motion, called peristalsis, which serves to push the contents of the colon along toward the outside of the body as water is absorbed and the stool becomes more solid. If there is a blockage inside the colon, cramping pains can occur. The pains often come and go, rather than being constant. This pain is most often felt in the abdomen, but when obstruction is partial or early and causing constipation, a vague sensation of fullness and bloating may result. Due to the obstruction, feces are not fully evacuated so people with colon cancer may frequently have the sensation that bowel movements are incomplete and may begin to spend a lot of time in the bathroom attempting to alleviate the sensation.

Acute Abdominal Pain and Colon Cancer

In some cases, tumors may grow unnoticed or undetected until serious damage and weakening of the wall of the colon has occurred. In such cases, perforation, meaning a hole, may form through the wall of the colon in the vicinity of the tumor. When this occurs, tenderness to pressure and pain occur at the site of the perforation. If the hole is large enough to permit leakage of the contents of the colon into the abdominal cavity, acute pain with fever and inflammation can occur. Peritonitis, meaning inflammation of the lower abdominal cavity, can be acutely painful. The abdomen becomes extremely tender to touch, and walking and even breathing and coughing--anything the moves the inflamed intestines about in the inflamed abdominal cavity--is painful. Acute peritonitis is a surgical emergency, and the perforation in the intestinal wall must be repaired.