**12. Secondary prophylaxis of colorectal adenomatous polyps and CRC**

Secondary CRC prevention is used for early detection of premalignant adenomas and cancer in its curative stage. It includes: screening colonoscopy; polypectomy; optimal treatment of IBD patients; chemoprevention and follow-up (Hawk, 2004; Rex, 2000). The aim of secondary prophylaxis or screening is to diminish the mortality of CRC by early detection and treatment of premalignant adenomas and cancer in its curable stage. European and national gastrointestinal and digestive endoscopy societies recommend screening to comprehend all healthy and risk groups of people. CRC screening consists of: digital rectal examination, fecal occult blood test, fecal immunochemical test for haemoglobin/haptoglobin, barium enema, sigmoidoscopy, sigmoidoscopy with fecal occult blood test, colonoscopy (with polypectomy), chromoendoscopy, NBI and high-resolution colonoscopy, virtual colonoscopy - CT or MRI, fecal DNA test (Geissler & Graeven, 2005). A useful test is invented for early detection and follow-up of CRC, similar to the noninvasive serological and fecal tests used for detection of infection with *H. Pylori*. This test is based on the idea, that proliferating cells, especially malignant cells, are expressing special isoenzyme of pyruvate kinase (PK), which plays a significant role in glycolysis. This isoenzyme consists of 4 subunits in healthy cells, while in neoplastic cells there are 2 subunits. This dimeric form M2-PK is found in gastrointestinal neoplasms. Tumor marker M2-PK is found in the blood of 47.8% of patients with CRC, while fecal test is sensible in 80% of cases with CRC (Hardt et al., 2004).

We propose stratification of healthy population in *three* groups: patients with *moderate risk* for development of colorectal polyps and cancer; patients with *elevated risk* for development of colorectal polyps and cancer; patients with *extremely high risk* for development of colorectal polyps and cancer;

Risk and Protective Factors for Development of Colorectal Polyps and Cancer 199

Encouraging examples for this possibility exist. Low physical activity, high uptake of saturated fats and arterial hypertension were recognized as risk factors for cardiovascular diseases. For a few years broad public campaigns resulted in dramatic reduction of mortality from coronary heart disease. Similar results are obtained and in some countries, in which restrictive government politics for tobacco smoking exists. No single factor is responsible for CRC carcinogenesis, but combination of some important factors, which are

May be the true pathway is to seek some average healthy diet and lifestyle, which play preventive role for many diseases. This recommendation is especially useful for the persons who are genetically predisposed, because the environmental risk factors can promote faster

Revival of the healthy Balkan (Bulgarian) feeding habits from the first half of the 20-th century seems reasonable (Ribarova et al., 2004). More protective foods must be included in our daily meal and this task looks feasible. We have to consume regularly fruit, vegetables, cereals, low-fat dairy products, legumes, poultry, fish, sea products, fibers and to reduce the intake of animal fats, red meat and preserved food. We have to be physical active, restrict

Many countries introduced a large scale programs for reduction of risk factors and promotion of protective factors for CRC. Besides that, such programs are useful and for prophylaxis of cardiovascular diseases, some other cancers and important metabolite

1. Do not eat fatty food, smoked meat, fried foods, margarine, pork, red meat and egg-

7. Legumes, fish, low-fat dairy products and Bulgarian yoghourt are good source of

8. Consume at least 5 times per day fruits and vegetables (pears, melons, water melons,

10. Healthy cooking includes decrease of the fat added in the food, reduction of the

13. Avoid usage of preserved foods and prefer local, season`s, fresh or frozen fruits and

alcohol usage, and to avoid tobacco smoking and usage of grilled and fried food.

**14. Recommendations for prophylaxis of CRC according to our data** 

You must follow these rules to be protected from colorectal cancer:

5. Restrict the intake of refined sugar and white flour products

9. Prefer poultry, white meat, hares and fish from the meat

cooking temperature and refraining from the use of grilled food

associated with the diet and lifestyle, is crucial.

diseases, like diabetes mellitus II type and obesity.

4. Sustain high physical activity and do not be obese

grapes, peaches, onion, garlic, pepper)

6. Use plant oil, but not margarine

11. Do not use regularly laxatives 12. Avoid contact with petrol

carcinogenesis.

fried food 2. Do not drink alcohol 3. Do not smoke

proteins

vegetables

The *first* group includes all patients who have no family history for cancer and no personal history for polypectomy or cancer in the past.

The *second* group includes patients with family history for CRC or related neoplasia (stomach, mammary gland, endometrium, ovary, adrenal glands), patients with polypectomy of polyps with low-grade dysplasia, patients with large bowel resection due to CRC (5 years post-surgery), male gender.

The *third* group includes patients: with familial adenomatous polyposis (FAP), with polypectomy of polyps with high-grade dysplasia, patients with large bowel resection due to CRC (up to 5 years post-surgery), with Peutz-Jeghers syndrome, juvenile polyposis, Cowden`s disease, HNPCC, IBD patients, with acromegaly and ureterosigmoidostomy.

The most appropriate follow-up method of patients, who have undergone polypectomy, is colonoscopy. The intervals according to the patients` risk and starting age are summarized in Table 7.


Table 7. Starting age and intervals for screening colonoscopy.
