Value of multi-slice spiral computerized tomography for diagnosis of synchronous colorectal carcinoma: a retrospective study

Objective To compare the accuracy of multi-slice spiral computerized tomography (MSCT) with colonoscopy for diagnosing synchronous colorectal carcinoma (SCC). Methods We retrospectively analyzed all consecutive patients admitted to our institution with colorectal carcinoma between 19 September 2014 and 31 January 2020. Data on SCC patients who had undergone MSCT and colonoscopy were analyzed. Information on tumor location, tumor size, missed diagnosis by MSCT or colonoscopy, T stage, pathological type, and reasons for missed diagnosis was recorded and used to assess the diagnostic accuracies of MSCT and colonoscopy. Results Twenty-three cases met the inclusion criteria. MSCT plus colonoscopy had a significantly higher diagnostic accuracy (93.5%) than colonoscopy alone. There were significant differences in missed diagnosis rates of proximal cancer (34.8%) and distal cancer (4.3%) by colonoscopy. For MSCT, the missed diagnosis rate for tumors with a median long diameter of 1.25 cm (interquartile range 0.80, 1.50) was significantly lower than that for larger tumors (long diameter 4.00 cm; 3.00, 6.00). Conclusions MSCT is a valuable diagnostic tool for SCC that can effectively minimize the missed diagnosis rate of primary tumors when combined with colonoscopy.