Endoscopic ultrasound in the preoperative staging of gastric cancer: key messages for surgeons.

Gastric cancer (GC) remains a frequent and important cause of cancer mortality worldwide. Many factors affect the prognosis of GC, but invasion and metastasis are the leading causes of death. Due to the various stage-oriented therapies available, after the diagnosis of GC it is important to determine the staging preoperatively in order to choose the appropriate management. GC staging is the workhorse of endoscopic ultrasound (EUS). EUS can distinguish the different wall layers of the gastrointestinal tract as well as assess regional lymph nodes. Furthermore, samples of suspicious lesions or lymph nodes can be obtained by means of EUS-guided fine-needle aspiration (EUS-FNA). In this narrative review, we highlight the current status of the usefulness of EUS for GC staging, with focus on early GC that still remains a diagnostic and therapeutic challenge. In particular, the possibility to ameliorate the accuracy of EUS, in this context, by using instruments with increased ultrasound frequency is emphasized.