| [ Summary ] |
It is thought that "small" advanced colorectal cancers should be classified between "large" advanced cancers and early cancers. We are interested in the fact that "small" advanced colorectal cancers have recently increased in relation to the total number of cancers. In this study, the term "small" was classified as an advanced cancer under 2cm in size. During the period from April 1985 to June 1999 we diagnosed 782 cases of advanced carcinoma, which included 52 "small" cases, the percentage was 6.6%. The five year rates were as follows : '85-'89 3.1%, '90-'94 4.5%, and '95-'99 12.1%. We classified them into four groups macroscopically : pure depressed type, depressed with marginal elevation type, protruded type and LST (laterally spreading tumor) resembled type. The rates for each type was 44.2, 38.5, 17.3 and 1.9 %. 28 cases have been analyzed by which could be sufficiently evaluated as to surface structure (pit pattern) with magnifying colonoscopy. All cases had type V pit patterns and 85.7% were of the non-structural pit pattern (type VIN). It is concluded that "small" size advanced colorectal cancers have a resemblance to depressed type early cancers, and we suspect that depressed type early cancers may mature and develop into "small" advanced can-cers. |