Screening of colorectal early cancer by radiology

The incidence of colorectal cancer has been gradually increasing in Japan, and if the present rate of increase is maintained it has been estimated that it will become the most common of all malignant neoplasms by the year 2000. It has been proved that colorectal cancer can be completely cured, if it is treated in its early phase. Early cancer of the large bowel is defined as a cancer which is limited to the mucosal membrane or submucosal layer, regardless of lymph node and distant metastases. Detection of early cancer improves the overall curability of colorectal cancer. The greatest number of early cancers of the large bowel are polypoid lesions in their macroscopic form, and depressed lesions are rarely encountered. Accordingly, the first step in the detection of early cancer starts with the screening of polypoid lesion by radiology and endoscopy. This paper is concerned with diagnostic accuracy of radiology in the screening of colorectal cancer with endoscopic correlation