Fecal cytology in conjunction with immunofecal occult blood test for colorectal cancer screening.

Objective: To develop a simple method to extract and analyze the cytomorphology of epithelial cells from fecal samples and to compare the efficacy of fecal cytology with the immunofecal occult blood test (IFOBT) in colorectal cancer screening.

Study design: Fecal cytology and IFOBT were performed on fecal samples obtained from 41 patients with colorectal cancer; 34 patients with a small, single adenoma (<0.5 cm); and 20 without abnormality. The samples were obtained prior to colonoscopic examination. For fecal cytology, epithelial cells were exacted through filtration, centrifugation and cytocentrifugation and stained with hematoxylin-eosin prior to morphologic analysis.

Results: Fecal cytology and IFOBT test had similar levels of sensitivity for detecting colorectal cancer (75.6% vs. 68.3%, respectively), but fecal cytology had higher specificity than IFOBT (100% as compared to 85.2%, respectively, p<0.05 by chi2 test). Seven of 41 colorectal cancer patients (17.1%) with negative IFOBT were positive by fecal cytology analysis. Combining fecal cytology with the IFOBT test in an either/or scenario significantly increased the sensitivity of IFOBT test to 92.68% for colorectal cancer detection (p<0.05 by chi2 test) without compromising the specificity.

Conclusion: Fecal cytology augments the sensitivity of IFOBT in detecting colorectal cancers, and combining fecal cytology and IFOBT may provide an important simple and cost-effective alternative for colon cancer screening.