Supplemental Parenteral Nutrition During Postgastrectomy in Nutritionally at Risk Patient

* If a patient undergoes gastrectomy, which is a kind of major abdominal operation, he/she loses more than 5% of his/her body weight in 2 months after surgery. This point is one of the criteria of 'risk of malnutrition' according to Nutrition Risk Screening (NRS 2002) and the patient who corresponds to this criterion needs nutritional support.
* According to Nutrition Risk Screening (NRS 2002), moderate malnutrition is defined as the state that the patient orally intakes 25\~50% of recommended requirements; severe malnutrition is less than 25%.
* Meanwhile, when oral nutrition support was provided to patients after gastric cancer surgery, the patients' average daily intake during the first three months was about a half of the recommended requirements.

  * Putting together the facts i) that the patient underwent major abdominal operation, ii) that the weight loss rate exceeded 5% for two months, iii) that the average daily intake of patients during the first three months was about half of the recommended amount, the patients are eligible to be classified as a group who require nutritional support according to NRS 2002.

Therefore, it is intended to verify the efficacy and safety of supplemental parenteral nutrition by comparing Arm A, who are provided oral intake with supplemental parenteral nutrition, Arm B, who are provided oral intake only after curative gastric cancer surgery.

With at least 5 days of supplemental parenteral nutrition, we expect minimized body weight loss, favorable blood test result, eligibility for chemotherapy compliance, increased quality of life (QoL), decreased infection rate, decreased hospital stay, and decreased mortality.

Eligibility Criteria:
Inclusion Criteria:

1. Patients who will undergo curative gastric cancer surgery (total gastrectomy, distal gastrectomy, proximal gastrectomy, and pylorus-preserving gastrectomy)
2. A Malnourished patient who meets one or more of the following:

   * BMI ≤ 20.5 kg/m2: BMI will be measured 1 day before surgery
   * Rapid weight loss (decreased by more than 5% in 2 months)
3. Patients over 18 years of age
4. Patients who are expected to receive PN for more than five days after surgery
5. Patients who are able to eat orally, but cannot fulfill the recommened calorie requirement by oral intake alone.

Exclusion Criteria:

1. In case that the patients have already provided parenteral nutrition prior to the consent of the study (oral diet prior to consent has nothing to do with study)
2. In case that the patients need tube feeding
3. Patients who are contraindicated to parenteral nutrition: heart failure (if the patient has current symptoms or receiving heart failure treatment, if ejection fraction(EF) was less than 40% in preoperative echocardiogram), Child-Pugh score C, renal failure (patient with 50% increased creatinine more than upper normal limit, patients currently undergoing renal replacement therapy), and pulmonary edema (appropriate chest X-ray signs for pulmonary edema), and the patient who suffered from allergie reaction to parenteral nutrition solutions.
4. Patients who are not easily able to obtain venous pathways or are vulnerable to side effects due to venous pathways (e.g. increased infection risk due to immunosupressant status)
5. Vulnerable subject (those who lack the decision making ability, pregnant women, or women who are planning to conceive)
6. Other patients whom the investigator has determined to be inappropriate to participate in this study