Is Colonoscopy Truly Needed for Very Elderly Patients Aged 85 Years or Over With Positive FOBT?

Abstract

Introduction: As the Japanese population continues to age, the number of fecal occult blood test (FOBT)-positive elderly individuals detected by medical screening is increasing. However, as these individuals have various underlying diseases, colonoscopy may not be the best option because of the risk of complications. We performed colonoscopy in FOBT-positive elderly individuals and investigated the final diagnoses and treatments offered. Methods: A total of 77 FOBT-positive elderly patients (>85 years old) who visited our department between June 2011 and June 2015 were examined by colonoscopy. Those with visible blood in the stool were excluded. Final diagnosis based on colonoscopy findings, and subsequent treatments were investigated. Results: Subjects included 36 men (mean age, 87.4 years; oldest age, 92 years) and 41 women (mean age, 87.9 years; oldest age, 94 years). 16 patients were receiving oral antithrombotic therapy. Colonoscopy revealed no abnormalities in 28 patients, rectal ulcer in 1 patient, ischemic colitis in 2 patients, colon polyps < 5 mm in 21 patients (2 treated by endoscopic mucosal resection (EMR) / 19 untreated), colon polyps 6-10 mm in 14 patients (8 treated by EMR / 6 untreated), colon polyps 11-20 mm in 6 patients (2 treated by EMR / 2 treated by endoscopic submucosal dissection (ESD) / 1 untreated / 1 only biopsy), colon polyp 30mm in 1 patient(only biopsy) and advanced colon cancer in 4 patient (treated by laparotomy). Among 14 patients who underwent EMR/ESD, adenocarcinoma was not found, but found in 2 patients who underwent only biopsy. High-grade adenomas were found in 4 patients with polyps 11-20 mm, while low-grade adenomas were found in the remaining 9 patients. Only 1 complication was happened to 86 years old women. The complication was perforation in case of ESD (15mm polyp of ascending colon), but was improved by conservative medical treatment. Conclusion: The majority of very elderly FOBT-positive patients (>85 years old) without visible blood in the stool had no abnormalities or low-grade adenoma when the polyp was small, showing that advanced colon cancer was relatively rare. Considering their advanced age, colon polyps are unlikely to progress rapidly to cancer in very elderly patients. Thus, instead of offering colonoscopy to all very elderly FOBTpositive patients, non-invasive abdominal computed tomography may be useful to select those with suspected advanced colon cancer for further examination by colonoscopy.