Background/aims: Guidelines for current postoperative colonoscopic surveillance are not specified in colorectal cancer (CRC) patients with synchronous adenoma (SA). We performed this retrospective study to determine the postoperative colonoscopic surveillance interval for the CRC patients with SA.
Methods: One hundred and twenty-four CRC patients with SA (SA-group) and the same number of patients without SA (NSA-group) were selected from our database. Two groups were matched by the stage of CRC. Median colonoscopic surveillance period was 55 (12-99) months. The colonoscopic surveillance frequency and interval were similar between the two groups.
Results: Mean age was higher and male was more frequent in SA-group than NSA-group (p= 0.0001). The incidence of missed adenoma, advanced missed adenoma and metachronous adenoma (MA) were higher in SA-group (30.8% vs. 5.8% at 1st yr., p=0.0001; 4.4% vs. 0%, p=0.0001; 31.1% vs. 9.1% at 2nd yr., p=0.016) during the first consecutive two years of surveillance. The MA- and advanced-MA-free survival rate were lower in SA-group (24.6% vs. 6.6%, p=0.0001; 4.1% vs. 0%, p=0.02) during three years after surgery. Dysplasia of the SA (p=0.04; OR, 110.3; 95% CI, 1.13-10742.6) and presence of missed adenoma (p=0.036; OR, 43.6; 95% CI, 1.28-1490.1) were risk factors for the advanced MA on a multivariate analysis in SA-group.
Conclusions: Postoperative colonoscopic surveillance at first year after surgery is warranted in CRC patients with SA.