Is the distal hyperplastic polyp a marker for proximal neoplasia? A systematic review

CONTEXT: The current literature is unclear about the association between distal hyperplastic polyps and synchronous neoplasia (adenomatous polyps and cancer) in the proximal colon. OBJECTIVE: To estimate the prevalence of proximal neoplasia associated with distal hyperplastic polyps. DATA SOURCES: Database searches (medline and embase from 1966 to 2001) and manual search of the bibliographies of included and excluded studies, case reports, editorials, review articles, and textbooks of Gastroenterology. STUDY SELECTION: Studies describing the prevalence of proximal neoplasia in persons with distal hyperplastic polyps. DATA EXTRACTION: Demographics, clinical variables, study design, and prevalence of proximal neoplasia associated with various distal colorectal findings. DATA SYNTHESIS: Of 18 included studies, 12 involved asymptomatic individuals in which the pooled absolute risk of any proximal neoplasia associated with distal hyperplastic polyps was 25% (95% confidence interval [95% CI], 21% to 29%). In 4 studies where colonoscopy was performed irrespective of distal findings, the absolute risk was 21% (95% CI, 14% to 28%). The relative risk of finding any proximal neoplasia in persons with distal hyperplastic polyps was 1.3 (95% CI, 0.9 to 1.8) compared to those with no distal polyps. Among 6 studies of patients with symptoms or risk factors for neoplasia, the absolute risk of proximal neoplasia was 35% (95% CI, 32% to 39%) in persons with distal hyperplastic polyps. In 2 studies of screening colonoscopy, advanced proximal neoplasia (cancer, or a polyp with villous histology or severe dysplasia, or a tubular adenoma greater than or equal to1 cm) was present in 4% to 5% of persons with distal hyperplastic polyps, which was 1.5 to 2.6 times greater than in those with no distal polyps. CONCLUSIONS: In asymptomatic persons, a distal hyperplastic polyp is associated with a 21% to 25% risk for any proximal neoplasia and a 4% to 5% risk of advanced proximal neoplasia, and may justify examination of the proximal colon. Further study is needed to determine the risk of advanced proximal neoplasia associated with size and number of distal hyperplastic polyps.