Objective:To confirm the effect of preoperative oral nutrition therapy on patients with malnourished before liver cancer resection.

Study design:Prospective, randomized, controlled clinical study. Primary end point: incidence of all complications 30 days after surgery.

Inclusion Criteria:

• 1. Clinical diagnosis of primary liver cancer (including hepatocellular carcinoma, bile duct carcinoma, and mixed cell carcinoma)
• 2. No contraindications for surgery
• 3. Eastern Cooperative Oncology Group (ECOG) score of preoperative physical state <2 points
• 4. Preoperative liver function score Child-Pugh ≤ 6 points: total bilirubin ≤ 3.0 mg / dl, albumin ≥ 28 g / L, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) ≤ 5 times the upper limit of normal
• 5. Voluntarily enter the study and sign the informed consent form, and communicate well with the researcher

Exclusion Criteria:

• 1. Patients who took fish oil supplements within 3 weeks before the study began
• 2. Patients with severe nutritional risk: serious nutritional risk should be considered when combining any of the following conditions: weight loss > 10% within 6 months; digital pain score (NRS) score > 5 points; BMI <18.5 kg/m2 (all patients with severe nutritional risk undergo individualized supportive care);
• 3. Patients with malignant tumors in other parts
• 4. Patients who are pregnant or lactating
• 5. Patients with mental and neurological disorders who cannot cooperate with medical staff
• 6. Patients with severe diabetes or poor glycemic control
• 7. Patients cannot tolerate nutritional preparations
• 8. Other circumstances that the researcher considers inappropriate to participate in the study