What is colon cancer?
It is a malignant tumor that can affect any part of the colon including the rectum. It originates in an uncontrolled proliferation of the cells of the colon mucosa, which give rise to a polyp. Over time this polyp can invade the colon wall, nearby lymph nodes and distant organs, such as the liver or lung, giving rise to metastasis.
The importance of colon cancer lies in its frequency: it is estimated that this year in Spain some 30,000 new cases will be diagnosed, which means that one out of every 20 people will develop colon cancer during their lifetime.
Can it be prevented?
The positive thing about colon cancer is that it can be diagnosed early and prevented. In primary prevention, we would treat cancer risk factors such as obesity, smoking, alcohol, sedentary lifestyle, a diet rich in fat and red meat, etc.
However, where we gain the most, where it has been demonstrated that mortality from colon cancer is reduced, is in secondary prevention, which consists of the detection of premalignant lesions and their removal by colonoscopy, a tremendously reliable technique.
Another option would be the detection of occult blood in feces, because we know that polyps leak blood. It is a less reliable technique, less sensitive than colonoscopy, but, when it is positive, we do the colonoscopy.
What is the recommendation to follow?
The colon cancer prevention strategy can vary depending on health policies and patient risk, but in short, a high-risk patient, who has a family history of colon cancer, who has already had polyps removed, should have a colonoscopy every five years after the age of 50 and sometimes even earlier.
The individual at medium risk, who is over 50 years of age without this history, it is advisable to have an annual or biannual fecal occult blood test and, when positive, a colonoscopy in order to detect and eradicate or remove premalignant lesions, preventing them from progressing to cancer and thus avoiding mortality.
What does colonoscopy consist of?
When I speak of colonoscopy I am referring to optical colonoscopy or video colonoscopy, not virtual colonoscopy, because this does not have the possibility of performing biopsies or removing lesions. As its name suggests, video colonoscopy is a flexible device that is inserted through the anus, which has a camera at its distal end and allows us to visualize the entire mucosa of the colon from the anus to the cecum.
If we see a tumor, we can biopsy it, if we see a polyp, we can remove it, we can recover it for analysis, which is important. As we can see, it is an invasive exploration, therefore it is uncomfortable and it has to be done correctly with sedation or anesthesia. Another condition is that the colon has to be clean, for which the patient will have to take a preparation.
There is some risk, such as post polypectomy bleeding, which we can control by endoscopy, or perforation, which may require an operation, but the final balance is positive. With colonoscopy we have managed to reduce mortality from colon cancer.