Investigation of colorectal cancer by minimal preparation CT in the frail and elderly patient

Abstract

Purpose: Frail&elderly patients frequently struggle with invasive colonic investigations and cathartic bowel preparation, commonly resulting in incomplete&inconclusive studies. Minimal preparation CT (MPCT) is a well tolerated alternative. Patients undergo a single scan following 48 hours of oral contrast, without the vigorous bowel preparation or colonic insufflation required for CT colonography. This study aimed to assess the accuracy of MPCT in the detection of colorectal cancer (CRC) in this population. Methods: A retrospective analysis of the outcomes of all 207 patients who underwent MPCT at a large district general hospital between 2005 and 2009. Results: All 11 CRC were correctly identified by MPCT, with a sensitivity of 100% and negative predictive value of 100%. The suspicion of CRC which subsequently proved benign was raised in 29 patients, resulting in a specificity of 84% and positive predictive value of 27.5%. Of these patients, 24 had an abnormal colon at the suspicious site, with diverticular disease of the recto-sigmoid the most common lesion. There was one examination failure where the patient chose not to drink the oral contrast provided. Conclusions: The sensitivity of MPCT compares favourably to colonoscopy, which is frequently compromised by poor views or incomplete intubation in this population. MPCT was well tolerated and the majority of questionable lesions were easily characterised by flexible sigmoidoscopy. In frail patients unable to withstand routine bowel preparation or colonoscopy, MPCT is an effective and reliable investigation, and can be routinely used for the exclusion of clinically relevant CRC.