Diagnostic accuracy of the gastric cancer T-category with respect to tumor localization

PURPOSE: Diagnosing early gastric cancer (EGC) or advanced gastric cancer (AGC) according to T-category is important for optimal GC treatment; however, the clinical and pathological diagnosis of tumor depths can sometimes vary. This study investigated the accuracy of clinical diagnosis of the tumor depth from the viewpoint of tumor localization and prognosis of patients with GC with discordance between clinical and pathological findings. METHODS: This study enrolled 741 patients with primary GC who underwent curative gastrectomy. Based on the clinical and pathological diagnosis of T-category, the patients were classified into four groups: Early-look EGC, Early-look AGC, Advanced-look EGC, and Advanced-look AGC. Tumor localization was classified longitudinally (the upper [U], middle [M], and lower [L] parts and cross-sectionally (the anterior [Ant] and posterior [Post] walls, and the lesser [Less] and greater [Gre] curvatures). RESULTS: Of the 462 clinical EGC cases, 52 were Early-look AGC cases that exhibited a significant association of tumor localization with the Post and Less in the U and M locations (UM-PL; p = 0.037). An Advanced-look EGC (p = 0.031) and Advanced-look AGC (p = 0.025) were independent prognostic factors for relapse-free survival each in pathological EGC and AGC, respectively. CONCLUSIONS: Patients with clinically diagnosed EGC but with pathologically diagnosed AGC more frequently presented tumor in the UM-PL than in any other location. Selection of therapeutic strategy according to the clinical diagnosis might be critical; however, it should be also considered that the accuracy of preoperative assessments varies with tumor localization. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00423-020-01971-3) contains supplementary material, which is available to authorized users.