**2. Risk and protective factors for colorectal polyps and cancer**

Today it is widely accepted that colorectal polyps (CRP) are preneoplastic lesions of colorectal cancer (CRC). From the 3 major groups of polyps: adenomas, hyperplastic, and serrated polyps, with the first group having the highest malignant potential. Hyperplastic polyps are the most common benign lesions, possessing very low malignant potential, and therefore do not require colonoscopic surveillance. However, recent studies prove their role in the classical model of adenoma-carcinoma sequence, and reveal common molecular features between normal mucosa, colorectal polyps, and cancer: proliferation activity, p53 overexpression, hypomethylation of c-myc, and mutations in k-ras oncogene (Hamilton, 2001). Progression of adenomas to CRC has been proven by the 'multistep model' of carcinogenesis, proposed by Fearon and Vogelstein. According to this model the stepwise progression of aberrant crypt foci, small, middle and large adenoma to carcinoma is accompanied by accumulation of mutations in the genes APC, k-ras, DCC, and p53 (Fearon, Fogelstein, 1990). Serrated polyps are histologicaly characterized by 'saw-tooth' infolding of the crypt epithelium, and are seen in 1% of the cases (Longacre & Fenoglio-Preiser, 1990). Every adenoma of the colorectum has a 5% probability for malignant transformation (Winawer et al., 1997). The growth of small adenomas is slow, requiring 10 years on average for doubling of their size (Hoff, 1987). The percentage of transformation of small adenomas into carcinomas is 0.25% (Eide, 1986). CRC is caused by complex interactions between host genetic susceptibility and certain exogenous risk factors. Geographic variation underscores

Risk and Protective Factors for Development of Colorectal Polyps and Cancer 181

Peutz-Jeghers syndrome, aged 31±12 years were included in the study. As a control we used a group of 42 healthy individuals (18 female and 24 male), aged 55±12 years, to whom upper and lower endoscopy was performed at their will or as a screening procedure, but showed no changes. Careful personal history, including dietary habits, physical examination, and anthropometric data were taken from all patients. We studied some factors from the lifestyle and diet in our patients with CRC and CRP, and looked for any connection between these factors and the beginning of CRC and CRP. For the aim of our study, we divided food consumed from the patients into 13 groups as follows: I. Milk and dairy products; II. Eggs; III. Meat and meat products; IV. Fish and sea animals; V. Cereals and pasta; VI. Sugar and sweets; VII. Legumes; VIII. Nuts; IX. Fats; X. Vegetables; XI. Fruits; XII. Spices; XIII. Beverages. We tried to establish the preferred way of cooking and favorite drinks in the studied patients. We registered their dietary habits in qualitative and quantitative manner, until the moment of CRC or CRP occurrence. We analyzed family predisposition of the included patients and their exposition to deleterious exogenous factors. All information, including clinical data, endoscopic and histological results, surveillance, and treatment, was entered on personal cards and in a

Logit-models were used for determining the possible risk or preventive factors, which combine regression and correlation analysis. We investigated the influence of these factors upon included patients with linear regression analysis to be able to associate the lifestyle and diet habits of population in our region. Depending on the value of the Exponent Ехp(B), factors are classified in three groups: risk factors – Exp(B)>1, protective factors – Exp(B) <1 and indifferent factors – Exp(B)=1. Statistical analysis was performed using Microsoft Excel, Statistics 5. 13./W and SPSS 13.0 for Windows software programs. Values of p<0.05 were

Our data find the following risk factors for colorectal polyps: consumption of red meat, meat products, sausages, fat food, high BMI, frequent use of laxatives, beer and alcohol intake, preserved foods, salty foods, grilled or barbecued meat, low physical activity, allergy, bacon, ham, margarine, fried food, preserved meat, sugar, marinated food, tobacco smoking, egg-fried food, working in heavy or petrol industry, presence of autoimmune disease, use of microwave oven, professional exposure to extremely low temperatures,

We concluded that the most important risk factors for the development of colorectal polyps are diet factors - consumption of sugar products, fried, grilled and preserved food, animal fats and margarine, egg-fried food and obesity. The most important life style and occupational risk factors for the development of colorectal polyps are: chronic alcohol intake, long lasting tobacco smoking, minimal physical activity, occupational exposure to petrol and metals. The chronic alcohol intake includes usage of beer, wine and strong drink. Substantial factors are and presence of autoimmune disease or allergy, frequent use of

**4. Risk factors for colorectal polyps according to our data** 

gastrointestinal register for polyps and cancer.

**3.2 Statistical analysis** 

considered as statistically significant.

passive smoking and elevated serum glucose level.

laxatives and elevated serum glucose level.

the importance of environmental factors in CRC pathogenesis, since a 30-40 fold difference between regions with high and low incidence has been found (Parkin et al., 1999). It is famous that the main risk factors for CRC and CRP are obesity, high calories intake, high body mass index (BMI), and low physical activity, consumption of red meat and animal fats, and alcohol. Other risk factors include male gender, advancing age, use of laxatives, constipation, pathological gut flora, some occupations, and intake of Fe-containing supplements. There is association also between the risk of developing CRC or CRP and presence of some diseases like inflammatory bowel disease (IBD), acromegaly**,** diabetes mellitus, cholecystectomy, ovarian and breast cancer, history of survived cancer or availability of adenomatous polyps in the past. Many conditions increase the risk of development of CRC and the degree of their influence substantially varies, as is shown in Table 1.


Тable 1. Assessment of risk factors for CRC and CRP. FAP, Familial adenomatous polyposis; NHPCC, Hereditary non-polyposis colorectal cancer; MAP, MYH-associated adenomatous polyposis; IBD, inflammatory bowel disease.
