Background: There is now evidence from three randomized controlled trials (from Minnesota, Nottingham and Funen) that screening average-risk individuals for colorectal cancer (CRC) with fecal-occult-blood tests (FOBT) can reduce mortality from CRC. In Japan, mortality rates from CRC have increased and mass screening with FOBT has been performed since 1992. Although there is growing proportion of CRC with FOBT, there is no conclusive evidence that they reduce mortality from this cause. We evaluated the feature of CRC with FOBT, as one of the methods for evaluation of the efficacy of screening with this test.
Methods: Between January, 1982 and December, 1996, 2071 cases with CRC resected in our hospital were considered. We evaluated the clinicopathological findings about age, sex, location of tumor, size depth, incidence of lymph node metastasis, stage and prognosis of CRC with FOBT (376) compared with CRC with no screening (controls; 1695).
Results: CRC with FOBT were earlier stage and smaller-sized cancers than controls. No significant difference was found in the incidence of lymph node metastasis at each depth and prognosis in each stage.
Conclusions: By screening with FOBT, we can detect at an earlier stage and with a smaller cancer, with the same biological behavior as controls. Now, we must encourage colon screening, continuing to research ways to improve identification of high-risk subgroups and increase complicance.