The 2011 edition of the NCCN Clinical Practice Guidelines for Gastric Cancer has been updated based on a large body of evidence-based medicine. At the 4th NCCN Asia Conference on Gastric Cancer, Professor Ilson, Weill Medical College of Cornell University, USA, reported on the key points of this update in an outline. Surgical Update TNM Staging Based on the 7th edition of the American Joint Committee on Cancer (AJCC) criteria in 2010, the new version of the guidelines has adjusted the TNM staging of gastric cancer, with stricter limits on N-staging and the former T3 being classified as T4a (lesion involving the plasma membrane or peritoneum). PET Some studies have shown that positron emission tomography (PET) can detect about 17% of lesions that cannot be detected by conventional CT and magnetic resonance imaging (MRI), especially small retroperitoneal lymph nodes and bone metastases. However, PET is deficient in the detection of small peritoneal metastases, with approximately 36% of patients not being visualized on PET. For early evaluation of the efficacy of chemotherapy for combined gastroesophageal tumors, Professor Ilson emphasized that PET scan results at 2 weeks after chemotherapy can be a better predictor of survival and a basis for preoperative chemotherapy response assessment and treatment selection. ) rates were significantly higher than those who did not respond to PET. EMR Endoscopic submucosal resection (EMR) is feasible in patients with Tis (carcinoma in situ) and stage T1a, regardless of physical assessment, in experienced centers. patients with stage T1b are recommended to consider surgical treatment because of lesion invasion to the submucosa and possible lymph node metastasis. Endoscopic submucosal dissection (ESD) is not recommended in the guidelines because it is not performed much in the United States. Positive peritoneal cytology The absence of visible peritoneal metastases, but positive peritoneal cytology is clearly defined as stage M1 and surgical treatment is not recommended. Paclitaxel combined with radiotherapy for sensitization Preoperative radiotherapy or chemotherapy is recommended for M0 patients in good health with unresectable tumors, and a new recommendation for paclitaxel-based regimens combined with radiotherapy for sensitization is added. GAST-3 Recommendations for postoperative management of patients who did not receive preoperative treatment are given in the new GAST-3 section. no postoperative treatment is required for Tis or T1N0 patients after R0 surgery. patients with T2N0 stage can be treated with observation or radiotherapy combined with [fluorouracil (FU) or paclitaxel-based regimen combined with radiotherapy sensitization] or given capecitabine single agent chemotherapy. Chemotherapy alone (capecitabine) or radiotherapy should be considered for patients with T3 or higher staging, and the former is preferred in the guidelines. The new version of the guidelines recommends for postoperative radiotherapy that experienced centers may perform intensity-modulated radiotherapy (IMRT) to reduce radiotherapy toxicity. For the management after R1 or R2 resection, radiotherapy or chemotherapy should be considered, with the addition of paclitaxel-based chemotherapy. The paclitaxel + carboplatin regimen was also recommended because it is more convenient to administer than FU drip. HER2 screening Based on the results of the ToGA study, the guidelines recommend that trastuzumab treatment be considered for inoperable locally progressive, recurrent or metastatic gastric or gastroesophageal union cancer. Immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) should be used to detect human epidermal growth factor receptor 2 (HER2) overexpression before treatment, and scoring criteria for IHC determination are given. Recurrent metastatic gastric cancer treatment update Drug selection Studies have shown that capecitabine and oxaliplatin (OXL) are not inferior to FU and cisplatin (DDP), respectively, for recurrent metastatic gastric cancer, and the incidence of thrombotic events is lower in the OXL group than in the DDP group. Therefore, capecitabine and oxaliplatin were recommended as Class I evidence instead of FU and DDP. Recommendation of two-drug combination The attempt to apply the treatment model of colon cancer to gastric cancer treatment has obtained satisfactory results. OXL+5-FU+calcium folinic acid (FOLFOX) and 5-FU+calcium folinic acid+irinotecan (FOLFIRI) regimens can be considered for first-line treatment of gastric cancer. And in terms of toxicity, the colon cancer chemotherapy regimen was more advantageous than the conventional gastric cancer chemotherapy regimen. The three-drug combination regimen did not show a significant advantage over the two-drug regimen. The modified docetaxel in combination with FU and DDP regimens has reduced toxicity and may benefit patients in good health. Addition of second-line regimens The guidelines add recommendations for second-line therapy, including FOLFIRI, FOLFOX, irinotecan combined with DDP, and docetaxel alone or combined with paclitaxel + irinotecan regimens. Although the level of evidence is not high, it also reflects the importance of second-line treatment for recurrent metastatic gastric cancer. Targeted therapy Several attempts on the vascular endothelial growth factor (VEGF) and epidermal factor receptor (EGFR) pathways have not yielded surprising results. Several phase III studies of targeted agents (lapatinib, cetuximab, etc.) in combination with chemotherapy are ongoing. Currently, only HER2 testing has been recommended as a reference for treatment selection, and trastuzumab may be applied in patients with strong HER2 positivity.