Abstract
We performed population-based screening for colorectal cancer using immunological faecal occult blood tests (latex agglutination assay with a cut-off of 100ng/ml) with two consecutive stool samples in the total of 631,906 subjects aged over 40 during 5 years between April 2000 and March 2005. To evaluate the effectiveness of population-based screening for colorectal cancer, we compared the recall rate for further examination, that of individuals who underwent further examination, the overall cancer detection rate, the detection rate of cancer excluding in-situ stage and the positive predictive value for cancer according to the gender of subjects and the cut-off value of immunological faecal occult blood tests. In this study statistical significance was evaluated by chi-square tests.
In conclusion, in order to achieve a high detection rate of colorectal cancer, reducing recall rate, the cut-off point of immunological faecal occult blood tests should be set at 130 ng/ml and the rate of individuals who underwent further examination should be raised by 10 % in the population screening of the subjects aged over 40. If we only consider the achievement of the current detection rate for cancer excluding in-situ stage as the goal of the population-based screening, the cut-off point of immunological faecal occult blood tests could be raised up to 150 ng/ml. Even in case that the cut-off point of immunological faecal occult blood tests is set at 150 or 200 ng/ml, the overall cancer detection rate and the detection rate of cancer excluding in-situ stage was exceeding the age-adjusted incidence rate of colorectal cancer in both genders of the subjects.
