STATISTICAL EVALUATION OF 2001 CARCINOID CASES WITH METASTASES, COLLECTED FROM LITERATURE - A COMPARATIVE-STUDY BETWEEN ORDINARY CARCINOIDSAND ATYPICAL VARIETIES

This study aimed at obtaining a better understanding of the malignant characteristics of carcinoids (gutendocrinomas) of the digestive syste m. After excluding cases with no possible individual identification as for age and sex, 2001 carcinoid cases with metastases among 5647 of t he digestive system computerized in the Niigata Registry were thus sub ject to the present analysis. These cases were divided into two groups : [A] 1719 with ordinary carcinoid histology and [B] 282 with atypical varieties including argyrophil (endocrine) cell carcinomas, small/oat cell carcinomas of endocrine type, composite carcinoid-adenocarcinoma varieties and other neuroendocrine tumors. In many aspects, a compara tive analysis demonstrated statistical differences between [A] and [B] : average age (55.7 vs 60.1), the rates of metastases (34.4% vs 55.6%) , the association of carcinoid syndrome (21.4% vs 2.8%), tumor size 20 mm or less (42.2%:, vs 22.5%), depth of invasion down to the submucosa (21.6% vs 11.7%) and transmural invasion (34.3% vs 47.7%), immunohist ochemistry of neuron-specific enolase (86.5% vs 66.7%), chromogranin ( 86.1% vs 67.6%), vasointestinal polypeptides, ACTH and alpha-fetoprote in, and the 5-year survival rate (61.4% vs 17.9%). No statistical diff erences between these two groups were found in the male to female rati o, serotonin activities and Grimelius argyrophilia. Although no genera lly acceptable definite criteria and definition for atypical carcinoid varieties have yet estabilished, neoplasias of this category seem to have a wide range of histological, histochemical, immunohistochemical, ultrastructural and biochemical features that may mostly be placed in between ordinary carcinoids and ordinary carcinomas.