Background: Colorectal cancer (CRC) is the third most common solid organ cancer in people living with kidney disease, and has a very poor prognosis, with less than 50% of kidney transplant recipients surviving one year after diagnosis. Our aims were to determine the prevalence of advanced colorectal neoplasms in pre-dialysis, dialysis and transplanted patients, and to evaluate the test performance characteristics of immunochemical faecal occult blood testing (iFOBT).Methods: Pre-dialysis, dialysis patients and those with transplants, between the ages 35-74 years from 10 centres in Australia, New Zealand, Canada and Spain received two screening iFOBTs, and those with at least one or more positive screens underwent colonoscopy. Advance colorectal neoplasms were defined as carcinoma or adenoma with at least one of the following features: 1 cm or more in size, or with villous components, or contains high-grade dysplasia. Results: From June 2010 to October 2014, 1436 patients with kidney disease [pre-dialysis: n= 656 (45.7%); dialysis: n=355 (24.7%) and transplant: n=425 (29.6%)] were recruited to the study. Overall, 311 (21.7%) were found to have one or more positive screens. Test positivity varied by CKD stage [pre-dialysis: n=120 (18.3 %); dialysis: n=94 (22.8%) and transplant: n=97(22.8%), p = 0.008]. The prevalence of advanced colorectal neoplasms pre-dialysis patients, those on dialysis and with kidney transplants were 3.8%, 6.8% and 5.2% (p=0.10), respectively. Within the specified follow-up time, a total of 6 colorectal carcinomas and 65 advanced colorectal adenomas were detected. The majority of these colorectal neoplasms (n= 30, 42.9%) were located in the sigmoid colon/rectum. The sensitivity and specificity of iFOBT were 98.6% (95% CI: 95.9% – 100%) and 82.2% (95% CI: 80.2% – 84.3%), with positive and negative predictive values of 22.5% (95% CI: 17.9% – 27.6%) and 99.7% (99.5% – 100%), respectively.

Conclusion: The prevalence of advanced colorectal neoplasms among those on dialysis and with kidney transplants appears to be higher than those with less severe CKD. The iFOBT displays acceptable test specificity and sensitivity for screening advanced colorectal neoplasms in patients with kidney transplants. A negative test effectively rules out a diagnosis of advanced colorectal neoplasm, but a diagnostic colonoscopy is required to confirm a diagnosis of neoplastic disease.

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