A multicenter, multiyear, case-controlled study of the risk of colonic polyps in patients with gastric polyps. Are gastric adenomas a new indication for surveillance colonoscopy?

A multicenter, multiyear, case-controlled colonoscopic study of 41 patients with gastric polyps undergoing colonoscopy analyzed whether patients with gastric polyps, particularly adenomas, run an increased risk of having colonic polyps. The primary controls were 109 patients undergoing colonoscopy matched for age and colonoscopy indications. A secondary control group was 69 of these 109 patients who, in addition to matching for age and colonoscopy indications with study patients, had no gastric polyps demonstrated by upper gastrointestinal examination. Patients with nonmalignant mucosal gastric polyps had a significantly greater incidence than primary controls of colonic polyps [odds ratio (OR) = 3.19, OR confidence interval = 1.46 - 6.99, p < 0.004, chi(2)], colonic neoplasms (OR = 3.58, OR confidence interval = 1.56 - 8.23, p < 0.006, chi(2)), and colonic cancer (OR = 4.5, OR confidence interval = 1.05 - 19.4, p < 0.04, Fisher's exact test). Moreover, patients with gastric adenomas had a significantly greater incidence than did primary controls of colonic polyps (OR = 7.6, OR confidence interval = 1.29 - 44.7, p < 0.02, Fisher's exact test). The association between gastric and colonic polyps did not arise as an artifact of the significantly higher frequency of females in the study group because this association remained after patient stratification by sex. The higher risk of colonic polyps in study patients did not arise as an artifact of unappreciated gastric polyps in the primary controls because study patients also had a significantly higher risk of colonic polyps than the secondary controls (OR = 3.21, OR confidence interval = 1.35 - 7.63, p , 0.01, chi(2). Our retrospective case-controlled study suggests that gastric adenomas may be a new, significant risk factor for colonic polyps. A strong association would require that patients with gastric adenomas undergo surveillance colonoscopy to diagnose and remove colonic polyps. However, before we apply this finding to clinical practice, the apparent association should be confirmed by another, preferably prospective study.