Risk of colorectal cancer and endoscopic screening in families of patients with hereditary nonpolyposis syndrome of colorectal cancer.

Abstract

e12543 Background: Relatives of patients with hereditary nonpolyposis colorectal cancer (HNPCC) have an elevated risk of colorectal cancer (CRC) and adenomas. To determine the efficacy of endoscopic screening among relatives of patients with HNPCC syndrome. Methods: 50 relatives of the first and 17 relatives of the second-degree relatives of 127 families of patients with HNPCC syndrome was subjected to endoscopic screening (colonoscopy). Results: The analysis of cancer register database of families, which includes clinical and genealogical information about 1,505 patients with colorectal cancer (CRC) and 407 with the primary multiple malignant neoplasms (PMMN), found 127 (6.6%) families, which are consistent with Amsterdam criteria of HNPCC. Among the 1057 first-degree relatives malignancies were detected in 238 (22.5±2.7%). The CRC among of the first degree relatives of patients with HNPCC syndrome was identified in 118 (11.2±2.9%), which is 20 times the population frequencies (0.56±0.004%) (p<0.001). The frequency of aggregation of PMMN and adenomas of the colon was 1.8±3.1% (19) è 0.6% (6), respectively. Prevalence of PMMN in the general population is 0.009±0.0005%, and adenomas - 4.7±1.4%. From 809 of first degree relatives 50 were available for the survey, and from the 924 second degree relatives - 20. The endoscopic screening of first degree relatives found the presence of different pathology in 35(60.0%±8.3%) surveyed persons, including CRC – at 19(38.0±11.4%) (p<0.01), primary multiple colorectal cancer – at 6(12.0±14.5%), adenomas - at 5(10.0%). Among the surveyed second degree relatives the pathology was identified at 8(40±18.5%), primary multiple colorectal cancer at 3(15.0%), and adenomas of the colon – at 5(25%). Conclusions: Colonoscopy is an effective method for identifying malignant and benign tumors of the colon at relatives in the families of patients with HNPCC syndrome. A high percentage of cancer detected in these families need to refine the survey mode in order to identify early forms of cancer and its secondary prevention.