Sequential histopathology and cell kinetic changes in rat pyloric mucosa during gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine.

The effect of administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) at a dose level of 83 mg/liter in the drinking water was followed in the pyloric mucosae of male noninbred Wistar rats. Autoradiographic studies were done on animals killed after 10, 15, 26, and 36 weeks of treatment. In the normal-appearing mucosae of the rats treated with MNNG for 10 weeks, the number of epithelial cells per pit column was significantly increased over that in control rats. Simultaneously, a shift in the major zone of epithelial cell proliferation was noted in the treated rats. Along with the formation of a longer pit in MNNG-treated rats, the greatest number of DNA-synthesizing cells was displaced from the middle third of the pit in a downward direction toward the muscularis mucosa. In addition, at this early experimental time period, pits lined with more immature, cuboidal, mucus-depleted cells were recognizable. These pits not only had higher labeling indices than normal-appearing pits of the same animals but also expressed a dual nature with increased proliferative activity extending either upward to the luminal surface or further in a downward direction. Focal areas of cellular atypism were present by week 10 of treatment with a threefold to sevenfold greater DNA synthesis activity than that found in the normal-appearing mucosa of the same animal. A wide range of values in proliferative activity was found not only among invasive pyloric tumors within the same animal but also within different areas of the same tumor. The mechanism for the formation of adenomas and invasive adenocarcinomas is believed to be related to the dual character of the hyperplastic pits described.

Diagnosis and staging of esophageal and gastric cancer.

Rarely can a clinical diagnosis of cancer of the esophagus and stomach be made while the lesion is still early. By the time the patient has symptoms and reports them to the physician, these tumors are usually invasive. In high-risk populations, screening if feasible and patients with vague symptoms can be aggressively studied. Technical advances have aided in screening high risk individuals. Double contrast radiography and direct exfoliative cytology with brush smears have increased the diagnostic accuracy. In patients with esophageal strictures dilatation followed by biopsy has proven useful and safe. Gastric secretory studies of acidicity, pepsin, enzymes and tumor markers are not sensitive enough to be helpful. Serial studies of serum pepsinogen I in a high-risk individual may be of value, but this still needs confirmation. Most surgeons agree that preoperative staging can be helpful in predicting patients in whom a palliative procedure should be planned rather than a curative approach.

Surveillance and early diagnosis of colorectal cancer.

Colorectal cancer is a major health problem in western countries such as the United States. The annual incidence of more than 130,000 new cases, and the annual mortality of more than 60,000 people justifies a consideration of efforts for its control. New concepts of risk, better understanding of the adenoma-adenocarcinoma natural history, and new screening and diagnostic technology have provided a basis for possible preventive approaches. Trials are in progress evaluating the fecal occult blood test and sigmoidoscopy screening tests, and colonoscopy as a diagnostic and surveillance test. Evaluation of data from the trials requires many considerations regarding bias and validity. Although the data from screening trials appear to be promising, they are still preliminary. In the interim, guidelines have been proposed for screening strategies related to average risk and high risk groups. Considerably more work will be required in order to provide the scientific basis for the control of large bowel cancer. In addition, efforts will have to be directed toward the effective communication of new concepts, data and techniques to the majority of physicians who interact with the at-risk population. Efforts will also have to be directed to the public at large to enhance their compliance with the approaches to increase their awareness of colorectal cancer as an important disease and to eliminate their misconceptions. Finally the cost effectiveness of various screening strategies will have to be examined once data indicates a benefit of such approaches.

Hepatoportal arteriovenous fistula treated with detachable balloon embolotherapy.

Hepatic artery to portal vain fistulas were first reported in 1892. Symptoms of portal hypertension usually occur within weeks to months, once the fistula develops. Various attempts at surgical occlusion and embolization, with varying results, have been reported. This report is of a 33-yr-old woman who, 23 yrs after an automobile accident, was admitted with ascites and diagnosed as having a right hepatic artery-to-portal vein fistula (RHAPVF), which was successfully occluded via detachable balloon embolic therapy. The ascites resolved within 3 days of the embolotherapy, and subsequent follow-up revealed no recurrence of ascites during the next 18 months.

Surveillance for colorectal neoplasia: is patient adherence following treatment a problem?

This study was conducted in order to assess prospective adherence to surveillance colonoscopy and fecal occult blood testing (FOBT) at 1 year following treatment for an index lesion among colorectal cancer and polyp patients. The investigation was carried out in cooperation with two gastroenterology and two surgical practices in Philadelphia and surrounding communities. Subjects in this study were patients who were treated for colorectal cancer (N = 9) or polyps (N = 169) and were recommended to undergo surveillance colonoscopy at 12 months following treatment. Overall, 96 (54%) subjects underwent surveillance colonoscopy. Of the 178 subjects included in the study, 52 (29%) were willing to participate in an assessment of FOBT sensitivity in surveillance. Of the 52 subjects who were mailed an FOBT packet, 24 (46%) actually returned specimen. Of the 24 patients who returned FOBTs, 17 (71%) also underwent colonoscopy, whereas only 10 (36%) of 26 patients who did not do FOBTs underwent colonoscopy. These findings indicate that adherence to surveillance is low, and that adherence to FOBT may be a marker for adherence to colonoscopy.