A COHORT STUDY OF STOMACH-CANCER RISK IN MEN AFTER GASTRIC-SURGERY FOR BENIGN DISEASE

Background: For the past 40 years, investigators have suggested that there exists an increased risk of stomach cancer following gastric surgery for benign disease. Recent cohort studies have consistently identified an increased risk of stomach cancer beginning 20 years or more following gastric surgery. Validation of this association and elucidation of risk factors related to gastric cancer have been complicated by variability in study designs. Purpose: This cohort study was designed to investigate the risk of stomach cancer following gastric surgery and to identify patient and treatment characteristics that may alter this risk. Methods: Medical admission records of 17077 male militarv veterans hospitalized during 1970-1971 in U.S. Department of Veterans Affairs (VA) hospitals were examined. From this initial cohort, 1094 patients who died within the 1st year following gastric surgery were excluded. Data analysis was performed on the final cohort consisting of 15983 patients divided into the following two groups: 1) an exposed group (gastric surgery group) that included 7609 patients receiving gastric surgery for a documented benign disorder and 2) an unexposed group (comparison group) that included 8374 male patients randomly selected from all other hospitalized male patients in the patient database. The comparison group was matched to the gastric surgery group by age (within 10 years), race, hospital, and year of admission. Mortality follow-up utilized the following three sources to identify vital status: 1) the VA Patient Treatment File (1970-1988), 2) the VA Beneficiary Identification Record Linkage System (1970-1989), and 3) the National Death Index (1979-1988). Death certificates were obtained for 99% of the deceased patients. Analyses included estimations of risk using standardized rate ratios (SRRs) and proportional hazards techniques. Results: A statistically significant increase in risk of stomach cancer was demonstrated among males during the 20 years following gastric surgery (SRR = 1.9; 95% confidence interval [CI] 1.3-2.4; P = .0001). The risk of developing gastric cancer was greatest during the 2nd to 5th postoperative years (SRR = 2.8; 95% CI = 1.6-4.5; P<.01) and during years 11-15 (SRR = 2.5; 95% CI = 1.2-4.8; P<.01). Also, the risk of developing gastric cancer was greatest among those treated by gastrectomy for any type of ulcer (SRR = 2.6; 95% CI = 1.2-4.9; P<.01) and those having any type of gastric surgery when the primary diagnosis was gastric ulcer (SRR = 2.9, 95% CI = 1.4-5.3; P<.01). Conclusions: This study confirms that men undergoing gastrectomy for benign disease and men receiving any gastric surgery for gastric ulcer are at increased risk for developing gastric cancer. Unlike earlier studies, we find that the increased risk is not delayed for 20 years.