Immunochemical Fecal Occult Blood Test Screening Results prior to Colorectal Cancer Diagnosis

Abstract

Abstract Introduction/Objective Immunochemical fecal occult blood testing (iFOBT) is one of the options outlined by the standard of care guidelines from the U.S. Preventive Services Task Force (USPSTF) for screening for colorectal cancer in adults. The iFOBT assay is a convenient and reasonably accurate screening assay. It has been shown in the literature, through a metanalysis of iFOBT tests, that the overall sensitivity of iFOBT in the general population for detecting colorectal cancer within 2 years of follow-up across different medical settings is 0.79 (95% confidence interval 0.69-0.86). However, similar investigation in the veteran population is sparse, but would be important given the significant differences between the Veteran population and the general population including increased medical comorbidities. Methods/Case Report A search of all iFOBT testing performed at a regional Veteran Affairs Medical Center (VAMC) from 10/1/2018 to 6/4/2022 was performed to identify patients with both diagnosed colorectal cancer by pathology examination and iFOBT testing within 2 years prior to this diagnosis. The iFOBT result (at least one positive prior to diagnosis or always negative) prior to diagnosis with colorectal cancer was recorded once per patient. iFOBT results collected after the day the positive colorectal pathology specimen was obtained were excluded. Demographic information was also recorded. iFOBT testing was performed using the Polymedco assay product (Cortlandt Manor, NY). Results (if a Case Study enter NA) There were a total of 26 patients (25 males and 1 female) with diagnosed colorectal cancer. The patient age range was 37 to 88 years (average 70) with an ethnic composition of 12 of 26 (46%) African Americans, 13 of 26 (50%) Caucasian American, and 1 of 26 (4%) Native Hawaiian or other Pacific Islander American. 20 of the 26 patients (77%) of the patients had at least one positive iFOBT test result prior to their colorectal cancer diagnosis, which is within the published observation for the accepted sensitivity in the general population. Conclusion While there are differences between the general population and the veteran population in terms of medical comorbidities, the iFOBT test assay performed similarly to the general population in terms of sensitivity for colorectal cancer diagnosed within 2 years of the iFOBT assay and remains an important part of the standard of care for colorectal screening for both populations.