Abstract
The data from the mass examinations of residents for colon cancer in the Hida Region, Gifu Prefecture, were compiled to evaluate the status of fecal blood-negative colon cancer.
Of the 88,354 residents examined for colon cancer between 1993 and 2004, 5,666 (6.41%) were found to require detailed examinations, and 4,180 (73.8%) received detailed examinations. Colon cancers were detected in 152 residents as a result of the mass examinations (colon cancer detection rate: 0.17%). The colon cancers were detected at an early stage in 98 residents and at an advanced stage in 54. Pseudo-negative cancer was defined, based on the past examination history, as “colon cancer detected within 2 years after a negative response to the latest fecal occult blood test.” Pseudo-negative cancers were detected in 72 residents (early cancer in 48 and advanced cancer in 24), accounting for 47.4% of the total. Pseudo-negative cancers were mostly present on the side of the anus in the case of early cancer and in the colon on the right side in the case of advanced cancer. The pseudo-negative cancers were asymptomatic in most cases. Colon cancer cases overlooked in examinations were often discovered as a result of repeated annual examinations, suggesting that annual examinations and detailed examinations should be recommended to patients.
