Is a Positive Fecal Occult Blood Test Predictive of Worse Endoscopic Findings on a Subsequent Colonoscopy When Compared to Those Undergoing a Screening Colonoscopy, in an Underserved Population?

Purpose: The American Cancer Society and the Multi-society Task Force for Colorectal Cancer (CRC) recommend yearly fecal occult blood test (FOBT) with any positive result followed by colonoscopy. However, FOBT requires the patient to collect stool on 3 occasions and observe dietary restriction. This can cause inconvenience and result in noncompliance, probably more so in a lower socioeconomic stratum. We, therefore, aimed to determine if underserved patients undergoing a colonoscopy for positive FOBT have clinically more significant endoscopic findings than those undergoing a screening colonoscopy only. Methods: We performed a retrospective electronic chart review of consecutive patients who underwent colonoscopy over a period of 10 months in 2009 in a county hospital serving largely resource-poor patients. From these, patients with positive FOBT done for CRC screening who were then referred for diagnostic colonoscopy (Group A) were compared with those referred for average risk CRC screening colonoscopy(Group B). Results: Out of 309 patients included in the study, 123 (39.8%) were African American (AA), 118 (38.8%) Hispanic, 39 (12.6%) Asian, 26 (8.4%) White and 3 (0.9%) of other races. Overall, 83 patients (26.8%) had one or more neoplastic lesions: tubular, tubulovillous or serrated adenoma; 32% were AA, 25% Hispanics, 28% Asians and 19% Whites. Group A had 126 patients with a mean age of 57 years and 36 (28.5%) of these had neoplastic lesions. Group B had 183 patients with a mean age of 59 and 47 of these (25.6%) had neoplastic lesions (p= 0.6) (Table 1). The most common lesion was tubular adenoma. Two patients had tubulovillous adenoma and both were AA (1 woman) in Group B. Three patients (2 women) had serrated adenoma, all AA and 2 from Group A. Eleven patients had polyp/s ≥ 10 mm, 5 in Group A and 6 in Group B. In most cases, the endoscopic findings could not explain the positive FOBT. No patient had villous adenoma or CRC.Table 1Conclusion: There was no difference in the diagnostic yield of a colonoscopy between those who had a positive FOBT versus those who underwent a screening colonoscopy. The high rate of FOBT false positive results may be due to multiple factors (test counseling, compliance, language barrier, etc) but as currently implemented, appears to be an ineffective step for CRC screening in the underserved population. This underlines the need for a cost effective CRC screening test for this population.