An epidemiologic approach to cancer of the large intestine: the significance of disease relationships

A canine model of gastric and colonic polyps

Polyps were produced in the canine stomach and colon by a surgical technique. In a total of 18 dogs 26 polyps were produced in the stomach or colon. Twenty of the 26 polyps were viable when endoscopically and microscopically examined. Polyps of approximately 1 cm in diameter and 3 to 4 cm in length can be produced without sloughing. The gross and microscopic characteristics of the canine polyp are quite similar to the human condition. Obviously the adenomatous tissue of the polyp head was not reproduced, but this area is not generally cut during polypectomy. The surgical produced polyps appear to be useful as a model to study the effects of electrosurgical cutting and for training in the technique of polypectomy.

Colorectal carcinoma in adolescents implications regarding etiology

Between October, 1974 and December, 1976, 13 adolescent patients with far-advanced, poorly differentiated colorectal carcinoma had been referred to a pediatric cancer center. All patients received chemotherapy with vincristine, methyl-CCNU and 5-fluorouracil. Five of 13 patients are living, one of whom remains disease-free after 12 months of chemotherapy. Four of the patients were from urban areas and nine from rural areas. One of four from urban areas had intimate exposure to chemicals used in the production of cotton and soy beans. Eight of nine patients from rural areas also had exposure to farm or agricultural chemicals, and three of these patients were intimately involved with the spraying operations. Suggestions regarding etiology and causative factors for the development of carcinoma of the colon in adults have previously been advanced. Results of these studies suggest that alternate etiologies must be suggested for adolescent colorectal carcinoma.

Introductory statement on the progress of The National Large Bowel Cancer Project: its goals, objectives, and programs

The introductory lecture updates the state of the art bearing on cancer of the large bowel. Topics discussed include etiological factors, the pathology of the disease, the role of animal models, the early diagnosis of the disease, including biochemical markers, with emphasis on immunology, and finally therapy, including surgery, radiotherapy, chemotherapy, and the immunological approaches to therapy as identified in the ongoing activities of the National Large Bowel Cancer Project. Interesting aspects of complementing the traditional ways of treating colorectal disease are noted in the discussion of new approaches to chemotherapeutic treatment based on rational developments obtained throught the study of cell kinetics and cell turnover. It is pointed out that this and other interrelationships considered in the multidisciplinary experimental and clinical approaches provide important leads toward the understanding of the mechanisms of disease, discovery of causes and means of prevention, methods of earlier diagnosis, improved rational modalities of treatment, and, one hopes, more successful management.

Comparative epidemiology of carcinoid and oat-cell tumors of the lung

Oat-cell carcinoma and bronchial carcinoid share histologic features with the Kultschitzky cell, and this argues for a common origin from the Kultschitzky cell for these tumors. In this view, the carcinoid represents the less malignant form and the oat-cell carcinoma the highly malignant adenocarcinoma of the colon, the epidemiologies of the benign and malignant forms of tumor arising from the same precursor are similar. However, the epidemiology of carcinoid tumor and that of oat-cell carcinoma are different. Although the ectopic production of hormones links the two kinds of tumor, it is also seen in other histologic types of lung carcinoma. Lung carcinoids occur in the genetic disorder of multiple endocrine adenomatosis, suggesting a genetic etiology for at least some carcinoids. This contrasts with the exogenous etiologic agents of cigarette smoking, occupational exposure, and urban domicile for oat-cell carcinoma. All these strong differences between lung carcinoid and oat-cell carcinoma indicate a markedly different process of carcinogenesis, which casts doubt on the hypothesis of a common cell precursor.