Who is At Risk?

It is important to note that polyps, even large ones, and early cancer may not have any symptoms at all. Symptoms also depend on the site of the cancer and how far away it is from the end of the colon. When stools enter the colon from the small intestines, it is in a semi-solid state. As it stays and travels along the colon, the water in it gets absorbed by the colon and it becomes more solid.

As such, tumour in the right side of the colon do not usually cause much symptoms as the semi-solid stools can flow past most tumours quite easily. The cancer may bleed silently as it is mixed in the stools and cannot be seen with the naked eye. Patients with tumours here usually present late with symptoms of anemia (low blood levels). Symptoms of anemia include tiredness, feeling breathless when walking the same distance or climbing stairs, frequent giddiness.

At the left side of the colon, the stools are more solid. Therefore, any narrowing of the colon lumen results in the following disturbance of the bowel habit:

  • The stools might seem to be narrower in size.
  • Patients might also feel constipated as it is more difficult for the stools to squeeze through a narrower passageway. This might also alternate with diarrhea or loose stools as this type of stools can pass through the narrowed passageway more easily.
  • Patients might also notice blood coating the stools. As a general guide, the blood seen is usually dark red in colour.

For tumours in the rectum, the patient may have the sensation of incomplete passage of stools. This is because the presence of the tumour there imitates the presence of stools.

Other less specific symptoms include feeling of bloating and mucus in the stools. Pain is usually not a feature of colon and rectum cancer until it is at an advanced stage. One complication of the tumour is intestinal obstruction. This means that the entire passageway is blocked and the stools (and even flatus) are not able to pass through. This results in abdominal pain, distension and at a later stage, vomiting. Intestinal obstruction is an emergency medical condition.

Physical examination usually do not yield much signs unless the cancer is in an advanced stage. A hard mass in the abdomen is usually a sign of a large tumour. An enlarged liver signifies spread of the cancer to the liver. In some rectal cancers, a digital rectal examination where your colorectal doctor inserts a finger up the anus may pick up earlier cancers. As such, if your colorectal doctor thinks that you warrant a rectal examination, please do not decline or refuse for fear of discomfort or embarassment.