[Updates and interpretation on NCCN clinical practice guidelines for gastric cancer 2017 version 5]

The National Comprehensive Cancer Network (NCCN) issued the clinical practice guidelines for gastric cancer 2017 edition version 5, which has been fully updated for the treatment of gastric cancer, including systematic treatment, surgery and radiotherapy. This article review and summarize the updated NCCN clinical practice guidelines for gastric cancer in 2017 and try to interpret it. (1)Biomarkers: mismatch repair defect (dMMR) or high microsatellite instability (MSI-H), programmed death ligand 1 (PD-L1) and tumor Epstein Barr virus (EBV) status should be considered for patients with gastric cancer. (2)Treatment of advanced gastric cancer: the major update is the application of immunotherapy (Pembrolizumab, Nivolumab combined with Ipilimumab). (3)Adjuvant therapy after D2 resection and perioperative treatment: the guidelines recommended Capecitabine combined with Oxaliplatin as adjuvant therapy after radical operation, updated from category 2A to 1; although the 2017 edition of the NCCN guidelines have not yet been adopted, Docetaxel-based FLOT scheme has certain potential in adjuvant therapy for gastric cancer. (4) Radiotherapy: a more detailed definition of radiotherapy for gastric cancer in different locations, especially in high-risk lymphatic drainage areas, was updated. (5) Genetic risk assessment: the guidelines recommended genetic screening for gastric cancer, including hereditary diffuse gastric cancer (HDGC), Lynch syndrome, juvenile polyposis (JPS), Peutz-Jephers syndrome (PJS) and familial adenomatous polyposis (FAP). The NCCN guidelines continue to update based on new evidences, which is the embodiment of precision medicine in the treatment of gastric cancer. The biggest change in the 2017 gastric cancer guidelines is the updates of immunotherapy, which also suggests that the direction of the gastric cancer treatment began to turn to immunotherapy.