Microsatellite Status of Primary Colorectal Cancer Predicts the Incidence of Postoperative Colorectal Neoplasms.

BACKGROUND/AIM: Few studies have evaluated the risk of postoperative colorectal neoplasms stratified by the nature of primary colorectal cancer (CRC). In this study, we revealed it on the basis of the microsatellite (MS) status of primary CRC. MATERIALS AND METHODS: We retrospectively reviewed 338 patients with CRC and calculated the risk of neoplasms during postoperative surveillance colonoscopy in association with the MS status of primary CRC. A propensity score method was applied. RESULTS: We identified a higher incidence of metachronous rectal neoplasms after the resection of MS stable CRC than MS instable CRC (adjusted HR 5.74, p=0.04). We also observed a higher incidence of colorectal tubular adenoma in patients with MSS CRC (adjusted hazard ratio 7.09, p<0.01) and a higher incidence of postoperative tubulovillous/villous adenoma in patients with MS instable CRC (adjusted HR=8.50, p=0.03). CONCLUSION: The MS status of primary colorectal cancer influenced the risk of postoperative colorectal neoplasms.