Colorectal cancer is cancer of the colon and rectum, two important parts of the digestive system. Together, the colon and rectum form a long, muscular tube called the large intestine. The colon is the first five feet of the large intestine, while the rectum is the last six inches.
Partly digested food enters the colon from the small intestine, where water and nutrients are removed, and the rest turned into waste (stool). The waste passes from the colon into the rectum and then out of the body through the anus. Cancerous cells can develop in the colon and rectum to form malignant tumours that may be life-threatening if detected late. Malignant tumours can invade and damage nearby tissues and spread through the bloodstream or lymphatic system. When colorectal cancer spreads outside the bowel, cancer cells are often found in nearby lymph nodes and most often spread to the liver, damaging tissues even further.
Symptoms and causes of colorectal cancer
Research has shown that people with certain risk factors are more likely than others to develop colorectal cancer. In fact, colorectal cancer is most likely to occur as you get older, and more than 90% of people with this disease are diagnosed after the age of 50.
If you have colorectal polyps or growths on the inner wall of the colon and rectum, you are also at higher risk of developing colorectal cancer. Most polyps are benign, meaning that they are harmless, but some polyps like adenomas can become cancerous. Finding and removing adenomas can, therefore, reduce your risk of developing colorectal cancer.
A family history of colorectal cancer can also indicate a higher risk, especially if you have more than one close relative with the disease. Ulcerative colitis or Crohn's disease, also known as inflammatory bowel diseases, may lead to the development of colorectal cancer too. Smoking and fatty, low-fibre diets put you at higher risk as well.
Symptoms of colorectal cancer include:
Other health problems can cause the same symptoms, so anyone with these symptoms should see a doctor to be diagnosed and treated as early as possible. It is also important not to wait for pain before seeing a doctor as early stages of colorectal cancer do not usually cause pain.
Diagnosis and treatment
Screening tests can help Dr Elliot identify and remove polyps or cancer before you have symptoms. Finding and removing polyps reduces the risk of developing colorectal cancer too. A colonoscopy is the standard screening test for the detection of polyps and colorectal cancer. Dr Elliot may perform a colonoscopy if you have symptoms relating to colorectal issues or you are over the age of 50. During this procedure, tissue samples can be taken to conduct a biopsy and detect the presence of cancerous cells.
Dr Elliot may also perform a faecal occult blood test or rectal exam to identify signs of colorectal cancer as well. The faecal occult blood test can detect tiny amounts of blood in the stool, which can indicate cancer. Furth tests, however, will need to be conducted to find the source of the blood as this can sometimes be related to benign conditions such as haemorrhoids. During a rectal exam, Dr Elliot will insert a lubricated, gloved finger into your rectum to feel for abnormalities that could indicate the presence of polyps or colorectal cancer.
Treatment for colorectal cancer is more likely to be effective when the disease is found early. Treatment usually includes removing malignant, or cancerous, tumours and polyps. If the cancer is at an advanced stage, however, open surgery, chemotherapy and/or radiotherapy may be required.