Association of fecal occult blood tests results with colonoscopic findings in a general hospital and validation of the screening test

Abstract

AbstractGlobally, colorectal cancer is the third leading cause of cancer death among men and the second among women, corresponding to about 10% of all cancers. The Brazilian Ministry of Health and National Cancer Institute recommend the screening of colorectal cancer for people over 50 years-old with Fecal Occult Blood Test. Endoscopy is limited to patients with positive screening results. The aim of this study is to evaluate the incidence of malignant or premalignant lesions diagnosed by endoscopy in patients with positive or negative Fecal Occult Blood Test and assess the efficacy of Fecal Occult Blood Test to predict the finding of a malignant colorectal lesion. We carried out a cross-sectional study among patients with a Fecal Occult Blood Test result that were submitted to colonoscopy, in the same hospital, from March 2016 to July 2017. Sensitivity, specificity, positive and negative predictive value of Fecal Occult Blood Test compared to colonoscopy neoplastic findings was calculated. The total of 92 patients were enrolled, 52 (56.5%) were female, Fecal Occult Blood Test was positive in 42.4% of them and in 41 (44.6%) the colonoscopy showed abnormal findings. Polyps were the most frequent alteration, found in 20 patients (21.7%). Among the patients with polyps, 15 (16.3%) had neoplastic and 5 (5.4%) presented non-neoplastic polyps. The Fecal Occult Blood Test sensitivity for detection of neoplastic polyps was 66.7%, specificity 62.3%, positive predictive value 11% and negative predictive value was 94.2%. Considering the need for a screening method, Fecal Occult Blood Test showed to be an effective and reliable screening test that can be applied in public health programs to detect and prevent colorectal cancer.