[Which first-degree relatives of patients with colorectal neoplasias are at the highest risk]

The first-degree relatives of patients with colorectal neoplasias have higher risk of colorectal cancer than general population. The aim of our study was to identify first- degree relatives at the highest risk of colorectal neoplasia considering both their hereditary and nonhereditary risks.

We have analysed the results of colonoscopic examinations of the first- degree relatives done within the project and we have compared them with the epidemiologic data relevant to colorectal cancer that we obtained from first-degree relatives.

160 first- degree relatives (66 men, 94 women, mean age 48.2, SD ± 10.9 years) have undergone colonoscopic examination within the project, 105 (66 %) of them had no or nonneoplastic polyps, 55 (34 %) had neoplastic lesions. In the univariate analysis the risk factors for the occurrence of neoplastic lesions were: male sex (OR 2.30, 95% CI 1.18- 4.48, p = 0.014), age over 50 years (OR 2.78, 95% CI 1.42- 5.45, p = 0.003), sibship (OR 2.71, 95% CI 1.25- 5.87, p = 0.012), smoking (OR 2.37, 95% CI 1.21- 4.63, p = 0.012) and higher fat intake (OR 2.07, 95% CI 1.07- 4.04, p = 0.032). In the multivariate analysis only the age over 50 years proved significant (OR 2.84, 95% CI 1.32- 6.09, p = 0.007). The most of the neoplastic lesions in first- degree relatives were located in the right colon.

We can confirm high prevalence of neoplastic lesions among first- degree relatives. First-degree relatives at the highest risk are men over 50 years of age, siblings, smokers, who do not reduce dietary fat intake. This group of patients share both genetic and environmental risks and thus should be screened with the highest priority.