American Journal of Epidemiology Vol. 139, No. 7: 684-692
Copyright © 1994 by The Johns Hopkins University School of Hygiene and Public Health
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Large Bowel Cancer following Gastric Surgery for Benign Disease: A Cohort Study
1Departments of Obstetrics arid Gynecology and of Preventive Medicine and Epidemiology Loyola University Medical Center Maywood IL
2Department of Epidemiology and Biostatistics School of Public Health University of Illinois at Chicago Chicago IL 60153
Reprint requests to Dr. Susan Gross Fisher, Department of Obstetrics and Gynecology, Loyola University Medical Center, 2160 South 1st Avenue, Maywood, IL 60153
Early studies suggested that gastric surgery for benign ulcer disease was associated with a subsequent increase in the risk of large bowel cancer. Dietary fats, altered bacterial flora, and secondary bile acids are considered to play a major role in the disease etiology. Gastric surgery is known to alter bile salt metabolism as well as bacterial flora in the colon. This cohort study was designed to investigate the risk of large bowel cancer following gastric surgery for benign ulcer disease and to identify potential patient and treatment characteristics that may be associated with this risk. A cohort of 15,983 males was selected from Department of Veterans Affairs hospital admissions in 1970 and 1971. The exposed group (n = 7,609) included all males treated with gastric surgery (resection or vagotomy and drainage) for benign ulcer disease. The unexposed group (n = 8,374) was a random sample of all other male patients from the same time period and database. All subjects were followed through 1989 to identify vital status and cause of death. Deaths were identifiable by computerized linkage of the subjects' social se curity numbers with the Department of Veterans Aftairs Beneficiary Identification Record Locator System and the National Death Index. The cause of death was documented by two certified nosologists from the death certificates of 99% of the deceased patients. Statistical analyses included estimations of risk based on standardized mortality ratios and standardized risk ratios. In this selected cohort, no increase in large bowel cancer risk was detected (risk ratio = 0.81, 95% confidence interval 0.62–1 .05). The type of surgical procedure, ulcer diagnosis, age at the time of surgery, and length of follow-up did not alter the risk estimates. Unlike the previously identified increase in gastric cancer risk following ulcer surgery, no elevation in the risk of large bowel cancer following such surgery was detected in this study. Factors that may alter gastric surgery sequelae and resultant site-specific cancer risks deserve further investigations.
colonic neoplasms; gastrectomy; ulcer; vagotomy