Diagnostic validity of CT gastrography versus gastroscopy for primary lesions in gastric cancer: evaluating the response to chemotherapy, a retrospective analysis

This retrospective study was carried out to compare computed tomographic (CT) gastrography and conventional optical gastroscopy (GS) in order to evaluate the effectiveness of chemotherapy in primary gastric lesions.

Patients with unresectable advanced and unresected early gastric cancer who had primary lesions and had received chemotherapy were enrolled. For primary lesions, CT gastrography and endoscopic assessment were done after chemotherapy, based on the Japanese Classification of Gastric Carcinoma (JCGC) criteria, 13th edition, and the Response Evaluation Criteria in Solid Tumors (RECIST). For metastatic solid lesions including lymph nodes, CT assessment was done based on the RECIST criteria.

Data from 23 patients were analyzed. With median follow-up of 9.4 months (range 2–23 months), 58 examinations were assessed by GS and CT gastrography. Setting optical endoscopic results as the gold standard, the accuracy of CT gastrography for primary gastric lesions was 77.6 % (45 of 58) (weighted κ = 0.72; P < 0.01) according to the JCGC 13th edition criteria and 90.0 % (52 of 58) (weighted κ = 0.75; P < 0.01) according to the RECIST. When all results were divided into two groups [the non-progressive disease (non-PD) group and PD group], accuracy was 93.1 % (52 of 58) (κ = 0.81; P < 0.01), sensitivity was 100 %, and specificity was 75.0 % (12 of 16). In addition, the predictability of PD was 100 % (12 of 12). The four cases of failure in specification were the following: a case of gastric remnant cancer, a case with insufficient distension of the stomach, a healed case with stenosis and scarring, and a case in which the wrong position had been selected for the examination. The average period until PD was 9.9 months (range 5–18 months), and the concordance period between GS and CT gastrography was 7.2 months in both non-PD and PD cases.

There was good concordance between the evaluations of GS and CT gastrography. CT gastrography exhibited favorable results in accuracy as well as 100 % PD predictability, which implied the possibility of using CT gastrography as a substitute for endoscopic assessments at post-chemotherapy assessments.