Predictive factors for lymph node metastasis in early gastric cancer with signet ring cell histology: a meta‐analysis
Early gastric cancer (EGC) is defined as a malignant lesion confined to the mucosa and submucosa, regardless of the status of lymph node metastasis (LNM), according to the Japanese Society of Gastroenterological Endoscopy criteria issued in 1962. Previously, the standard treatment for EGC was radical surgery. However, with the development of modern technologies, less invasive surgery, such as endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR), is gaining popularity in EGC treatment because of fewer associated post‐operative complications and improved quality of life. According to the current guidelines, indications for less invasive surgery for EGC are differentiated mucosal carcinomas ≤20 mm in diameter without ulceration,1 which may be too strict and may lead to overtreatment for some EGCs. Generally, EGCs are divided into differentiated and undifferentiated types, the latter category comprising poorly differentiated carcinoma, mucinous carcinoma and signet ring cell carcinoma (SRC).2 Many studies have shown better prognosis for early SRC than for other undifferentiated subtypes in early stage.3 Moreover, the rate of LNM in early SRC (5.3–7.6%) was lower than that observed in other undifferentiated histologies (14.7–17.8%)4 and similar to that of differentiated EGC (8.2–9.8%),2 which cast early SRC as a potential candidate for treatment by less invasive surgery.9 Although many authors8 attempted to clarify the predictive factors for LNM and investigated the feasibility of using less invasive surgery in the treatment of early SRC, the results remain debatable.
The present study aimed to identify risk factors for LNM in early SRC by conducting a meta‐analysis, and hope the results of the present study can offer some help for surgeons to treat early SRC in future clinical practice.