Fecal occult blood test and flexible rectosigmoidoscopy: tools for the screening of colorectal neoplasms in asymptomatic patients

Abstract

Purpose To assess the feasibility and effectiveness of the fecal occult blood test (FOBT) and flexible rectosigmoidoscopy (RSS), as tools used in the CRC screening, in asymptomatic patients, from 50 years of age. Methods The study is transversal and presents a sample of 102 individuals. The FOBT used was the guaiaco, FECA-CULT® method, held at a single time, in feces collected from a complete evacuation. Individuals, who presented the positive FOBT, were sent to colonoscopy complement, although this is not primary variable examined in this study. All subjects underwent to flexible RSS, after bowel preparation, using a solution of sodium phosphate monobasic monohydrate and dibasic sodium phosphate heptahydrate. Results Individuals showed minimum age of 50 years and maximum 82 years, 61.6 years average and standard deviation +8.1. Of the 102 individuals, 42 (41%) belong to the males, whereas 60 (58.8%) female. The FOBT presented 10 positive cases (9.8%) (IC 95%: 4.8–17.3%) and 92 negative cases (90.2%) (IC 95%; 82.7–95.2%). The FOBT was effective at 2.9% and presented false-positive result in 6.9%. The result of the FBOT association with flexible RSS showed that 70% of neoplastic polyps showed no bleeding. Its sensitivity was 30% (IC 95%: 0.00–63.40%), the value of the relative risk was 3.94 (IC 95%: 1.20–12.89) and 5.20 valued odds ratio (IC 95%: −23.15 to 1.21). The specificity was 92.40% (IC 95%: 86.43–98.35%). The flexible RSS detected 15 polyps, among which, after histopathological study, 10 were neoplastic, being 09 adenomatous polyps (60%) and 01 malignity (6.7%) (IC 95%: 0.20–31.90%) and 05 non-neoplastic polyps (33.3%), and 03 inflammatory polyps (20%) (IC 95%: 4.3–48.1%) and 02 hyperplastic polyps (13.3%) (IC 95%: 1.7–40.5%). Neoplastic polyps were present in 60% of individuals over 60 years of age. Among the adenomatous polyps, the adenomatous polyp tubular prevalence is 53.33%. Among the 102 individuals, flexible RSS detected 09 adenomatous polyps (8.82%) and 01 (0.98%) malignity polyp. Conclusion The tools FOBT and flexible RSS presented feasibility and, when associated demonstrated statistical significance in detecting polyps in general and important clinical significance on the detection of adenomatous polyps and colorectal cancer.

FOBTs With Lower Detection Limits Increase the Colonoscopy Rates

“…(9,10). Considering that the transition from adenomatous polyps to adenocarcinoma takes an average of 10 years, screening tests to identify malignant polyps in the population are important in early diagnosis of colorectal cancer and reducing mortality and treatment costs (9)(10)(11).…”

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

“…Considering the evolution from adenomatous polyps to adenocarcinoma takes in average 10 years, screening tests to identify malignant polyps of the population are an important step to early detection colorectal cancer and a priority to reduce mortality and treatment costs. 2,3 In recent years, special attention has been given to the different modalities of colorectal cancer screening and their applications in populations with different grades of disease risks. 4 Among the screening methods, the Fecal Occult Blood Test (FOBT), a lab test used to check stool samples for hidden hemoglobin, has aroused interest.…”

“…10 The guidelines of the American Society of Gastrointestinal Endoscopy (ASGE) and the European Panel on Adequacy of Gastrointestinal Endoscopy II (EPAGE II) indicate colorectal cancer screening by colonoscopy, for asymptomatic patients with no family history of colorectal cancer older than 50 years every 10 years. 3,10 The Brazilian Ministry of Health and the Brazilian National Institute of Health recommend the Fecal Occult Blood Test (FOBT) screening of colorectal cancer for people over 50 years-old and colonoscopy is limited to patients with positive screening results. It is noteworthy that the colonoscopy use as a first screening method involves higher costs and is only accessible for a minority of Brazilians who have a private health insurance.…”