Clinical characteristics of patients with serrated polyposis syndrome in Korea: comparison with Western patients

BACKGROUND/AIMS: Serrated polyposis syndrome (SPS) has been shown to increase the risk of colorectal cancer (CRC). However, little is known about the characteristics of Asian patients with SPS. This study aimed to identify the clinicopathological features and risk of CRC in Korean patients with SPS as well as the differences between Korean and Western patients based on a literature review. METHODS: This retrospective study included 30 patients with SPS as defined by World Health Organization classification treated at Samsung Medical Center, Korea, between March 1999 and May 2011. RESULTS: Twenty patients (67%) were male. The median patient age at diagnosis was 56 years (range, 39–76 years). A total of 702 polyps were identified during a median follow-up of 43 months (range, 0–149 months). Serrated polyps were noted more frequently in the distal colon (298/702, 55%). However, large serrated polyps and serrated adenomas were mainly distributed throughout the proximal colon (75% vs. 25% and 81% vs. 19%, respectively); 73.3% had synchronous adenomatous polyps. The incidence of CRC was 10% (3/30 patients), but no interval CRC was detected. A total of 87% of the patients underwent esophagogastroduodenoscopy and 19.2% had significant lesions. CONCLUSIONS: The phenotype of SPS in Korean patients is different from that of Western patients. In Korean patients, SPS is more common in men, there were fewer total numbers of serrated adenoma/polyps, and the incidence of CRC was lower than that in Western patients. Korean patients tend to more frequently have abnormal gastric lesions. However, the prevalence of synchronous adenomatous polyps is high in both Western and Korean patients.

Pathogenesis and Management of Serrated Polyps: Current Status and Future Directions

Hyperplastic or serrated polyps were once believed to have little to no clinical significance. A subset of these polyps are now considered to be precursors to colorectal cancers (CRC) in the serrated pathway that may account for at least 15% of all tumors. The serrated pathway is distinct from the two other CRC pathways and involves an epigenetic hypermethylation mechanism of CpG islands within promoter regions of tumor suppressor genes. This process results in the formation of CpG island methylator phenotype tumors. Serrated polyps are divided into hyperplastic polyps, sessile serrated adenomas/polyps (SSA/Ps), and traditional serrated adenomas (TSAs). The SSA/P and the TSA have the potential for dysplasia and subsequent malignant transformation. The SSA/Ps are more common and are more likely to be flat than TSAs. Their flat morphology may make them difficult to detect and thus explain the variation in detection rates among endoscopists. Challenges for endoscopists also include the difficulty in pathological interpretation as well surveillance of these lesions. Furthermore, serrated polyps may be inadequately resected by endoscopists. Thus, it is not surprising that the serrated pathway has been linked with interval cancers. This review will provide the physician or clinician with the knowledge to manage patients with serrated polyps.