By Fotini Laoudi MD, Gastroenterologist, Endoscopist, Director of Gastroenterological Clinic, Paleo Faliro Clinic
Colon cancer is the most frequent digestive system cancer in developed countries and third most frequent malignancy in men (following prostate and lung cancer) and to women (following breast and lung cancer) in the USA.
In Europe, the colon cancer is the most common form of cancer. Each year there appear 310,000 new cases while about 210,000 persons lose their life as a result of this disease. In the Mediterranean countries colon cancer has 20 to 40% lower frequency in comparison to the Scandinavian countries and the United Kingdom.
Therefore, it seems that the frequency of the disease differs significantly internationally, while the observation that people emigrating from low-impact countries to developed countries, tend to get colon cancer, leads us to the conclusion that besides genetic predisposition, environmental factors are of paramount importance to the development of the disease.
On such a serious issue, prevention is possibly the "key" for dealing with it. Prevention of colon cancer is distinguished in:
- Primary prevention, related to smoking, obesity, physical exercise, nutrition, medicines, toxic substances, etc.
- Secondary prevention, related to screening the population.
Primary preventions
- Smoking
The relative risk of smokers varies from 1.6 to 3.9. Smokers have 2-3 times higher risk for growing colon polyps with potential malignancy.
- Obesity
Obesity is an epidemic today in the countries that have adopted the "Western type" of nutrition and unfortunately it is the most important problem in children. Most studies support that the risk for developing colon cancer appears to be larger in the proximal part of the colon and with regards to the two sexes, the risk is greater to men.
The mechanism with which obesity is associated with colon cancer is not known. The view that obesity is considered low-grade inflammation which causes chronic hyperinsulinemia, with unfortunately undesirable results against target organs such as the colon, seems to be constantly gaining terrain.
Recently scholars have tried to analyze the relationship between physical exercise and risk colon cancer in more than 400,000 people in Western Europe. The results showed that physical activity at least 1 hour daily is associated with a decrease in the risk of developing colon cancer by 20-25%.
- Nutrition
The international academic journal is rich in studies relating colon cancer with dietary factors. Most results relate to following data:
- High consumption of red meat increases the risk of colon cancer by 70%, while fish and chicken showed negative correlation.
- A diet rich in animal fat and pre-cooked products increases the risk. Olive oil has serious anticancer properties attributed to monounsaturated fatty acids, to phenols and tocopherols.
- The great Pan-European Prospective Study (European Prospective Investigation into Cancer and Nutrition study) showed that the high consumption of fruit and vegetables is related to a reduction of colon cancer in both non-smokers and former smokers.
- Aspirin, calcium, selenium, the non – steroid anti – inflammatory drugs and antioxidants, mainly Vitamin C, seem to have protective action.
Secondary Prevention
It is based on the "effort to identify the disease to people who do not know that may be suffering from it" (Screening method). Today, screening the general population for colon cancer is divided into two categories:
- Fecal tests
- Anatomical structures tests
Fecal tests
- Fecal test for the detection hemoglobin (gFoBT). Easy, quick, safe, carried out by the patient at home and concerns collection of feces from one to three evacuations. Consumption of aspirin, non-steroid anti-inflammatory drugs, vitamin C, red meat, poultry and fish should be avoided three days before. The method has a sensitivity of 64.3 - 79.4% and a specificity of 87.5%.
- Immunochemical detection assay fecal hemoglobin (FIT). The examination detects human hemoglobin and does not require a diet. It has a sensitivity of up to 94% and a specificity of 87.5%. The most important element successful fecal tests is to commit the patients to repeated annual tests after the age of 50 and to compulsory colonoscopy on positive results.
- Stool test for the identification of pathological DNA (sDNA). The test detects pathological DNA cells (from adenomas and carcinomas) by means of 21 point mutations. It is a high cost method cost and therefore has a limitation in generalized acceptance as a screening test for the population.
Anatomical structures tests
- Sigmoidoscopy: It requires limited intestinal preparation (usually 2 enemas) and is carried out without sedation. It examines up to a depth of about 40 cm and has a sensitivity of 60-70% in detecting colon cancer, with regards to the left part of the bowel.
- Colonoscopy: It thoroughly examines the length of the colon. It requires preparation of the intestine and can apply to all people after being mildly sedated. It has low complication rate and combines the diagnostic with the therapeutics approach to the problems.
For all the above reasons it seems to be the test of choice for screening the population in the context of preventing colon cancer.
Although there are various views, the examination should begin at the 50th year of age and be repeated every 5 – 8 years for those who do not have findings. It seems to be the most popular approach.
- Double contrast barium enema: The application of the method has been decreasing lately. It requires significant intestinal preparation, causes discomfort to the patient and may have falsely positive results.
- Virtual colonoscopy (CTC): It is a method of getting 3D images of the colon through reconfiguring images of a CT scan. It requires intestinal preparation, has a high cost, is disadvantaged in identifying pathology from extraintestinal structures and needs to be followed by colonoscopy on positive findings.
Risk Factors for Colon Cancer
General risk
- Age> 50 years old
- Asymptomatic
Increased danger
- Inflammatory bowel diseases (IBD): Ulcerative colitis, Crohn’s
- Familial adenomatous polyposis, including Gardner's and Turcot's syndromes
- Hereditary non-polyposis colon cancer
- Hamartomatous polyposis syndromes, Peutz-Jeghers syndrome, Juvenile polyposis syndrome
- Family history of colon adenomas and cancer
- Individual history of adenomas in the colon, breasts, ovaries and uterus
In conclusion
The need to implement a program for screening and informing the public is necessary. Most Western countries have adopted guidelines for the right nutrition, for prevention and for the removal of harmful agents. All the above require a sensitized population and financial support.
The Paleo Faliro Clinic of Athens Medical Group applies a screening program for colon cancer at a very low cost, since it is obvious that prevention is the most an important step in dealing with the disease.
The Decalogue of Good Nutrition
- Consume fruit and vegetables daily
- Prefer seasonal products rather than frozen
- Consume plenty of plant residue
- Avoid animal fat and remove it from meat as well as the skin from poultry
- Use olive oil
- Prefer fish and legumes instead of meat
- Avoid eating a large number of calories
- Drink 8-10 glasses of water a day
- Alcohol consumption should not exceed 2 glasses of wine per day
- Eat with pleasure and tranquility
