A specific role of endoscopic ultrasonography for therapeutic decision-making in patients with gastric cardia cancer

The role of endoscopic ultrasonography (EUS) in gastric cardia cancer should be further evaluated because the accuracy of EUS depends on tumor location. We aimed to identify a specific role of EUS for therapeutic decision-making in patients with gastric cardia cancer. Initial EUS examinations for treatment-naive gastric cancer that were followed by endoscopic resection or surgery were included in the study. Lesions were classified as cardiac and non-cardiac cancer according to tumor location. The diagnostic performance of EUS in predicting invasion depth was compared between the two groups. The overall accuracy of EUS in predicting invasion depth did not differ between the cardiac and non-cardiac cancer groups (44.4 vs. 52.3 %, P = 0.259). The underestimation rate was higher in the cardiac cancer group than in the non-cardiac cancer group (37.0 vs. 18.5 %, P = 0.001). When the depth of invasion was predicted to be deeper than the mucosa (submucosal or deeper) by EUS, the positive predictive value was 82.1 [95 % confidence interval (CI), 66.5–92.5 %] and 62.9 % (95 % CI, 60.5–66.9 %) in the cardiac and non-cardiac cancer groups, respectively (P = 0.015). In multivariable analysis, tumor location in the cardia was found to be an independent factor for the underestimation of invasion depth [odds ratio (95 % CI) = 2.242 (1.156–4.349)]. The underestimation rate in predicting invasion depth was significantly higher for cardiac cancers than for non-cardiac cancers. Therefore, selection of the treatment method for gastric cardia cancer via EUS should be done carefully.