[The way of submucosal invasion of superficial sm cancers]

Nineteen superficial sm cancers were studied as for their way of submucosal invasion. The materials were obtained either by colonoscopic polypectomy or by surgical operation. The following were concluded: 1. The ways of submucosal invasion can be classified into three. There is a special type of superficial early cancer which penetrate the mucosal muscle at one point and reaches the deeper layer linearly or show expansive growth at the submucosal layer. 2. The speed of submucosal invasion is either earlier (at the size around 5 mm), or slower (over 15 mm). 3. There are no significant difference in the way of submucosal invasion between IIa and IIc subclasses of superficial early cancers. That is one supporting evidence that there is no fundamental difference among subclasses of shapes of superficial early cancers. 4. One reason why the diagnosis of superficial cancers is difficult is that not a few superficial cancers undergo early morphological change (to sessile form) due to massive submucosal invasion.