Findings in the distal and proximal colon in colonoscopy screening after positive FIT and related pre-procedure factors

ABSTRACT

Background: colonoscopy is the gold standard method forthe early diagnosis and prevention of colorectal cancer(CRC). Screening programs include immune determinationof blood in feces. Regardless of the method used, proximalcolon lesions appear to be detected less frequently.Objective: to analyze the characteristics of proximal anddistal lesions and possible predisposing factors.Methods: a cross-sectional study was performed of 692patients from the CRC screening program with fecal immunological test (FIT) ≥ 100 ngHb/ml (October 2017-October2018). The right colon was examined twice as patients wereparticipating in a randomized clinical trial to re-evaluatethe right colon by forward-viewing endoscope or proximalretroflexion. The adenoma detection rate (ADR), advancedneoplasia (AN) and CRC in the proximal and distal colon,histological and morphological characteristics in each section were analyzed.Results: in the study, 52.9 % of the patients were male, witha mean age of 59.5 years (standard deviation [SD] 7.6);1,490 polyps were found and the ADR was 57.7 % (distal42 % and proximal 37 %). Detection rates were 45.8 % forAN, 40.9 % for advanced adenomas, 5.2 % for advancedsessile serrated lesions (SSL) and CRC was diagnosed in4.8 % of patients. Males had more AN than females. Themean age of patients with AN was significantly higher. ANwere associated with smoking and alcohol consumption (p = 0.0001). Globally, FIT levels were higher in patientswith AN (p = 0.003). Sixty-six per cent of cancers were distally located and 61.3 % of CRC were diagnosed in the earlystages.Conclusions: in an average-risk asymptomatic populationundergoing colonoscopy after positive FIT, AN were morecommon in the distal colon in males, older patients, smokers and those with alcohol intake. (AU)