Relationship between the fecal occult blood test and benign anal disorders.

Background/aims: The fecal occult blood test is a very useful method for mass screening for colorectal cancer. The possibility of the fecal occult blood test being positive is high even in benign anal disorders, but the relationship between anal disorders and the fecal occult blood test has not been fully studied.

Methodology: During the period from November 1995 to April 1996, we performed both fecal occult blood test and sigmoid colonofiberscopy for 440 patients with anal disorders who visited our hospital for the first time.

Results: The positive fecal occult blood test rate was 18.8% (77/409) for those who had only anal disorders and no findings in the colon and rectum. The positive fecal occult blood test rate was significantly high in the cases with polyps (42.3%) and in those with colorectal cancer (60%).

Conclusions: These findings suggested the need to analyze fecal occult blood test, keeping in mind that fecal occult blood test might be positive even without any malignant findings in the large intestine in about 20% of cases of patients have anal disorders when fecal occult blood test is performed.