Most bowel cancers start as benign innocent growths – called polyps – on the wall of the bowel. Polyps are like small spots or cherries on stalks and most do not produce symptoms. Polyps are common as we get older and most polyps are not pre-cancerous. One type of polyp called an adenoma can become cancerous (malignant). If left undetected the cancer cells will multiply to form a tumour in the bowel.
If untreated, the tumour can grow into the wall of the bowel or back passage. Once cancer cells are in the wall, they can travel into the bloodstream or lymph nodes; from here the cancer cells can travel to other parts of the body. For bowel cancer, the most common places for bowel cancer cells to spread to are the liver and the lungs. The process of spread is called metastasis.
The earlier bowel cancer is caught, the easier it is to treat. 75% of bowel cancer is curable if caught early. This is why it is so important to know the signs and symptoms of bowel cancer.