The efficiency of endoscopic ultrasound in pretherapeutic assessment of the depth of invasion in early gastric cancer

Abstract

Aim: Increased applications of endoscopic mucosal resection (EMR) and laparoscopic surgery accentuate the importance of accurate evaluation of the depth of invasion in the treatment of early gastric cancer (EGC). We evaluated the efficiency of endoscopic ultrasonography (EUS) in the staging of EGC. Methods: The accuracy of EUS in pretherapeutic evaluation of EGC was analyzed retrospectively. Pathologically proven 53 gastric cancers with suspicion of early stage by endoscopy and CT were evaluated with EUS followed by surgical (37 cases) or endoscopic resections (16 cases). The results of EUS staging were compared to the postresection histological staging. Results: The overall accuracy of EUS in differentiation between mucosal (m) and submucosal (sm) cancer was 62.3%. The depth of m and sm cancers was correctly assessed by EUS as 58% and 70%, respectively. The rate of overstaging was 32.1%(17/53) while that of understaging was only 5.7%(3/53). One case of EMR needed further treatment. Statistical analysis was carried out to verify the factors that affect the accuracy of EUS. The included variables were size, groß type, site, differentiation, associated intestinal metaplasia, and Ming & Lauren classification of tumor. Differentiation of tumor showed statistical significance (p<0.03) on diagnostic accuracy of EUS. Well differentiated adenocarcinoma had the tendency of accurate EUS staging. Conclusions: Endoscopic mucosal resection is a good modality for the treatment of EGC. However, when the patients are not accurately selected, EMR should be followed by additional second stage surgical treatment. Although the accuracy of EUS in differentiation of m and sm gastric cancer was relatively lower in this study, higher accuracy in well differentiated adenocarcinoma and the overstaging tendency have positive aspect of reducing the necessity of second stage operation.