Growth Patterns of Gastric Cancer

Early gastric cancer cases were analyzed in terms of growth patterns of the superficially speading (Super) type and the penetrating growth (Pen) type, the latter further subdivided into the Pen A-type which grows expansively and the Pen B type which has infiltration. This classification was then extended to include advanced cancer, and the natural history of gastric cancer was studied. While the Super type showed good prognosis after surgery, then Pen A type had a poorer prognosis except when confined to the mucosa. The prognosis of the Pen B type, which was good for cases in early stages, became poor once the lesion invaded the serosa. Such growth patterns were further studied in terms of cytophotometric DNA analysis. It was found that most Super-type cases have low ploidy, while most of the Pen A type have high ploidy and the Pen B type, which had retained low ploidy in the submucosal stage, developed high ploidy when the invasion reached the serosa. Such analyses led us to postulate that early cancer of the Super type progresses to the funnel-shaped advanced cancer with relatively good prognosis, while the Pen A type grows into box-shaped lesions corresponding to Lauren’s intestinal type, while the Pen B type became the mountain-shaped ones of the diffuse type. Based on data from annual check-ups, it was estimated that initially occurring low and high ploidy cancer may be approximately equally distributed. Thus, it is important to bear in mind that diagnostic advances may actually favor the detection of slow growing, low-malignant lesions, overlooking rapidly growing highly malignant lesions in their early stage before detection, thereby allowing them to progress to an advanced stage.