Endoscopic submucosal dissection of early gastric cancer with mixed-type histology: Protocol for a systematic review...

Endoscopic submucosal dissection (ESD) is a primary treatment for the early gastric cancer (EGC) who have a negligible risk of lymph node metastasis satisfying specific criteria. These criteria are histologically categorized by EGC with differentiated-type histology (EGC-DH) and undifferentiated-type histology (EGC-UH). However, gastric cancer is histologically heterogenous and there has been no specific criteria for EGC with mixed-type histology (EGC-MH). Moreover, therapeutic outcomes of ESD for EGC-MH have not been clearly described.

We will search the core databases (MEDLINE (through PubMed), the Cochrane Library, and Embase) from their inception to November 2018 using pre-established searching strategy by 2 independent evaluators. The P.I.C.O. is as follows; Patients: who have EGC-MH, Intervention: ESD, Comparison: none, Outcome: at least one among the rate of complete resection, curative resection, en bloc resection, recurrence or procedure-related adverse event that enabled an evaluation of feasibility of ESD. All types of study design will be sought and publications in English with full-text will be included. The risk of bias will be assessed using the ROBINS-I tool. Descriptive data synthesis is planned and quantitative synthesis will be used if the included studies are sufficiently homogenous (pooled therapeutic outcomes data with 95% confidence intervals). Publication bias will be assessed with quantitative analyses if more than 10 articles are enrolled.

The results will provide evidence for validity of current ESD criteria in addition to the technical feasibility of ESD for EGC-MH.

This study will provide evidence of ESD for EGC-MH.