Risk of Proximal Colon Neoplasia With Distal Hyperplastic Polyps

Background: Most guidelines for colorectal cancer screeningdonotconsiderdistalhyperplasticpolyps(HPs) to be markers for proximal colon neoplasia. However, many studies have shown an increased risk of proximal neoplasia (PN) in patients with distal HPs. We performed a systematic review to assess the association between distal HPs and PN. Methods:Weidentifiedstudiesthatcomparedtheprevalence of PN and proximal advanced neoplasia in patients with distal HPs vs controls. Two masked investigatorsextracteddataonindividualswithdistalHPs,distal adenomas, or no distal polyps. Using the DerSimonian andLairdmethod,wecalculatedsummaryriskratios.Extensive subgroup analysis was performed. Results: The prevalence of PN and proximal advanced neoplasiainpersonswithdistalHPswas26.0%and4.4%, respectively. In studies comparing the risk of PN in patients with distal HPs vs those with no distal polyps, the summary risk ratio was 1.81 (95% confidence interval, 1.20-2.73). However, this increased risk disappeared if only high-quality studies on screening patients were considered. The risk ratio was 0.69 (95% confidenceinterval,0.60-0.80)whencomparingtherisk of PN in those with distal HPs vs those with distal adenomas. Conclusions: Overall, patients with distal HPs have an intermediate risk of PN compared with those with distal adenomas or no distal polyps; however, in asymptomatic screening individuals, there is no increased risk of PNorproximaladvancedneoplasia.ThediscoveryofHPs on screening flexible sigmoidoscopy should not automatically prompt follow-up colonoscopy. Arch Intern Med. 2005;165:382-390