Abstract
In order to clarify the target age group for whom colorectal cancer screening should be strongly recommended, we studied 11,415 patients with colorectal cancer. All were at least 40 years of age based on the Miyagi Prefectural Cancer Registry data. We investigated according to sex and age, clinical stage, and prognosis of cancers detected by screening and cancers detected on an outpatient basis. In addition, using these results, we calculated the expected years of life saved by screening. Men between 55 and 74 and women between 55 and 79 years of age were considered to be in the optimal target age group for intensive screening. It appeared to be adequately meaningful to recommend screening to men between the ages of 75 and 84 and women between the ages of 80 and 84, if they were in good general health. In individuals aged 85 years or older, prognostic improvement with screening would appear to be minimal, and aggressive recommendation of screening for this age group was thus considered to be unnecessary. An increase in cancer incidence, an extension of average life expectancy, and an improvement of compliance with diagnostic examination have considerable influence on the effectiveness of screening. Therefore, appropriate assessment is necessary depending on the situation in the future.
