Colorectal cancer is any cancer of the large intestine (the colon and rectum). The most common symptoms are blood in the stool, a change in bowel movements, weight loss and constant fatigue. Although it can be caused by genetic factors, age and lifestyle are by far the most common causes. Poor diet, obesity, smoking, lack of physical activity, processed meat and alcohol are all risk factors. Patients with some sort of inflammatory bowel disease also have a higher risk. It is the third most common form of cancer worldwide, and is more common in the developed world than the developing world. It is more common in men than women.
The stool guaiac test is the most common screening device and, being non-invasive, is commonly performed as part of a regular check-up for any patient over the age of 50. If the test is positive, the patient is usually scheduled for a colonoscopy. If a polyp is found, it is usually routinely removed and, if found to be malignant, the patient will be scheduled for radiology to see if the disease has spread.
Treatment for the condition is usually a combination of surgery, chemotherapy and radiation therapy. However, the survival rate is only fair, even if the cancer has not penetrated the wall of the colon. As such, particularly for patients at risk, lifestyle improvements are recommended to prevent the disease - generally a diet rich in fruit and vegetables. In addition, NSAIDs such as aspirin appear to be helpful in preventing the condition.