HER2 status	Grade I recommendations	Grade II recommendations	Grade III recommendations
Positive	Trastuzumab in combination with fluoropyrimidine/capecitabine + cisplatin (Evidence 1A)	Trastuzumab in combination with other first-line chemotherapy regimens (e.g., oxaliplatin + capecitabine or S-1 + cisplatin) (Evidence 2B)	Trastuzumab in combination with other first-line chemotherapy regimens excluding anthracyclines (Evidence 3)
Negative	Cisplatin + fluoropyrimidine (5-FU/capecitabine/S-1) (Evidence 1A)	Three-drug combination regimens (e.g., DCF and mDCF) may be suitable for patients in good physical conditions and with large tumor burden (Evidence 2A)	Three-drug combination regimens (e.g., ECF and mECF) may be suitable for patients in good physical conditions and with large tumor burden (Evidence 2A)
	Oxaliplatin + fluoropyrimidine (5-FU/capecitabine/S-1) (Evidence 2B)
	Docetaxel + 5-FU/capecitabine/S-1 (Evidence 2B)	Single-drug regimens (e.g., fluoropyrimidine- or taxanes-based therapy) may be suitable for those in poor physical condition (Evidence 2B)	Irinotecan-based chemotherapy (Evidence 3)
	Paclitaxel + 5-FU/capecitabine/S-1 (Evidence 2B)

ECF epirubicin + cisplatin + 5-FU, DCF docetaxel + cisplatin + 5-FU, mDCF modified DCF