Clinicopathologic and biomolecular features of interval colorectal cancers in Korean patients: A KASID multicenter prospective study

BACKGROUNDInterval colorectal cancer (CRC) refers to CRC diagnosed after an index colonoscopy before the next recommended surveillance examination.Our previous multicenter retrospective study showed that, unlike Western studies, interval CRCs developed more often in men and on the left side.Few studies on interval CRC in Asia have focused on its biomolecular features. AIMTo identify the clinicopathological and biomolecular features of Korean patients with interval CRCs. METHODSA prospective multicenter cohort study involving 107 patients newly diagnosed with sporadic or interval CRC from six referral hospitals in Korea was conducted.Propensity score weighting was used to balance patient characteristics. RESULTSIn contrast with Western studies, Korean interval CRCs were more common in male patients and in the left colon.The most commonly suspected etiology of CRCs is missed lesions, followed by incomplete resection, incomplete colonoscopy, and newly developed cancer.In multivariable Cox proportional hazard analysis, advanced stages [stage III: Adjusted hazard ratio (aHR), 9.58; 95% confidence interval (CI): 1.97-46.51,stage IV: AHR, 25.36; 95%CI: 4.09-157.10vs stage I] and CpG island methylator phenotype (+) (aHR, 45.15; 95%CI: 8.09-251.9)were risk factors for survival.On the other hand, body mass index (aHR, 0.82; 95%CI: 0.70-0.96),microsatellite instability (aHR, 1.27e -8 ; 95%CI: 2.00e -9 -8.12e -8 ), BRAF (+) (aHR, 0.08; 95%CI: 0.01-0.44)were protective factors for survival. / 40 CONCLUSIONTo the best of our knowledge, this is the first study on the clinicopathological and biomolecular features of Korean interval CRCs.There were several differences in the clinicopathological and biomolecular features of interval CRCs between Korean and Western populations.Further large-scale multicenter studies are required.