Background: It is known that postoperative malnutrition remains inevitable for gastric cancer patients with adjuvant chemotherapy, which could have prejudicial influence on the compliance of subsequent adjuvant chemotherapy and survival of the patients. A multi-institutional prospective phase 2 study had demonstrated the efficacy of oral nutritional supplements (ONS) for gastric cancer patients undergoing gastrectomy. However, previous studies did not focus the gastric cancer patients with adjuvant chemotherapy. Thus, it is unknown whether the ONS could benefit the gastric cancer patients with adjuvant chemotherapy. A multicenter, phase 3 randomised controlled trial was conducted to compare the ONS with standard diet for postoperative gastric cancer patients with adjuvant chemotherapy. Patients and method: In this study, pathological confirmed stage II-III or T1N1M0 gastric cancer patients who are supposed to receive adjuvant chemotherapy, aged from 18 to 75 years, with body mass index (BMI) from 18.5 to 28.0 kg/m2, and with Eastern Cooperative Oncology Group performance status ≤2, are randomized 1:1 to receive oral administration of NutrenOpimum (Nestle Suisse S.A.), a liquid enteral nutritional food for special medical purpose (FSMP), or standard diet. NutrenOpimum administration was recommended with a dosage of 400 kcal/400 ml per day within 7 days postoperatively and was continued for 3 months postoperatively. The primary end point was postoperative malnutrition, as defined as ratio of the weight loss at 3 months postoperatively to the days 7 postoperatively body weight (body weight loss ratio) higher than 10%; body weight loss ratio at 1, 3, 6 months. Secondary end points were chemotherapy withdrawal, time to adjuvant chemotherapy failure, period of adjuvant chemotherapy, quality of life, grade 3/4 neutropenia, thrombocytopenia, anemia, and severe side effects on digestive tract. Final study analysis will be conducted after the last patient's enrollment.

Inclusion Criteria:

1. be proven to be primary adenocarcinoma of gastric cancer and pathological confirmed stage II-III or T1N1M0
2. age: 18-75 years
3. Eastern Cooperative Oncology Group performance status: 0~2
4. body mass index: 18.5-28.0kg/m2
5. able to ingest semiliquid diet
6. without other malignancies with exception of the cured cervical carcinoma in situ and basal cell carcinoma
7. anticipated overall survival time ≥ 6 months
8. anticipated period of adjuvant chemotherapy ≥ 3
9. without severe mental disorder
10. without severe digestive disease
11. without Acquired Immune Deficiency Syndrome or diabetes mellitus
12. without communication barrier
13. informed consensus of patients

Exclusion Criteria:

1. with unstable hemodynamics
2. with severe nausea or vomit which cannot be controlled by drugs
3. allergic reaction to NutrenOpimum
4. dysfunction of other organs
5. with severe disease, such as infection, stroke, heart failure or stock
6. other situation to be judged not adaptive to the study by investigators