Frequency of Colonic and Extra-colonic Findings of CT Colonoscopy in Asymptomatic Patients: A Retrospective Analysis of Follow-up and Cost of Care

Abstract

Introduction: Colorectal carcinoma is the second most commonly diagnosed cancer and the second leading cause of cancer death. Though optical colonoscopy is considered as gold standard for the screening and diagnostic purpose approximately 40% of the U.S. population older than 50 years currently does not undergo colorectal cancer screening. CTC may represent a reasonable alternative for colonoscopy with 88.8% & 90% sensitivity for polyp ≥6mm and ≥ 10mm respectively. Objectives: To identify the frequency of colonic and of extra-colonic findings of CT colonoscopy in asymptomatic patients. To evaluate the cost of medical care incurred from subsequent follow-up evaluation of colonic findings. Methods: A retrospective study was conducted between Jan to Dec, 2014 at outpatient clinic. Asymptomatic patients aged 50-85 years of either sex were included in the study. Socio demographic, clinical and radiological data were extracted from medical records. Data entry and analysis was done on SPSS v. 22. CRADS system was used to characterize the colonic and extra-colonic findings. Results: A total of 150 asymptomatic patients with CT colonoscopy were included. Descriptive analysis showed mean age of 62.5 ±6 years. Approximately 55% patients were male, 18% were current smokers and 33% patient were obese [BMI >30]. 23 (15%) patients were found to have colonic findings. 13 were in category of C2 (colonic polyps 6-9mm in diameter or 10 in diameter or >3 in number with each 6-9 mm (C3). 63 out of 150 patients were found to have extra-colonic finding. Around 26% patients had clinically unimportant findings such as gall stone, simple liver cyst or hiatal hernia (E2). 11% had E3 which likely unimportant, e.g. complex renal cyst, or lung nodule. Approximately 6% were identified to have potentially important findings such as abdominal aortic aneurysm (4-5cm) or solid kidney mass. 7 (50%) patient from C2 category and 10 (100%) from C3 category were followed by diagnostic and therapeutic optical colonoscopy. Total cost of CT colonoscopy was $97500 ($650 each patient). 17 patients had follow-up optical colonoscopy and the cost incurred was $26,000 (patient payment depends on insurance copay). Conclusion: It is concluded that CT colonoscopy can be effective modality for screening of colorectal cancers in asymptomatic patients who are at average or moderate risk for developing colorectal carcinoma colonoscopy with an added advantage of finding extra colonic pathologies.