Cancers are the leading cause of death worldwide, and various modalities of cancer treatment, such as surgery, radiation therapy, and pharmacological therapies, have been applied. Malnutrition and a loss of muscle mass are encountered frequently in cancer patients and adversely affect the clinical outcomes. Therefore, screening for, monitoring, and treating malnutrition are important procedures in treating cancer patients. This paper reviews the guidelines as well as comparative studies describing the nutritional support provided to cancer patients and describes the evidence-based guidelines and recommendation for each topic.

Pediatric patients have characteristics such as a low capacity for storing energy/nutrients and high energy metabolism as compared those of adults. Because of the inherent characteristics that they are continually growing, supplying both rapid and adequate nutrition is of the utmost importance. In the case of children undergoing surgery (and particularly gastrointestinal surgery), there is a high possibility of a restricted supply of nutrition, and so active intervention to supply sufficient nutrition must be carried out. Of course, enteral nutrition is preferred, but continuous monitoring of nutrition is of paramount importance; thus, parenteral nutrition should be provided when necessary. Nutritional support requires continuous monitoring when and if complications arise. The complications of parenteral nutrition have yet to be overcome, so further research on this topic is certainly warranted.

Metabolic abnormalities and catheter-related infections are common complications of parenteral nutrition (PN). Particulate contamination is a catheter-related complication can occur when administering PN: mixing the electrolytes, trace elements, vitamins into the PN, or puncturing a rubber stopper at the PN formulation. In addition, the aggregation of the components of the PN solution by a drug incompatibility reaction could be related to particulate contamination. PN contaminated with precipitates, insoluble particles, and bacteria was reported as the cause of the death of a patient. The Food and Drug Administration recommended that the filters be used during PN administration. In-line filters can retain the bacteria and insoluble particles in PN solutions, and prevent their infusion into the patient. Therefore, in-line filters are recommended to prevent catheter-related complications that can occur during PN infusion. A 0.2µ filter for lipid-free PN and a 1.2µ filter for lipid-containing PN solutions can be used. On the other hand, when a filter is applied, the infusion rate can decrease and the economic burden will increase for patients requiring long-term PN. In addition, small particles, such as viruses, polymers, and proteins cannot be filtered out completely. In conclusion, in-line filers are recommended to prevent catheter-related complications that can occur during PN administration, but there are no international standardized guidelines. Therefore, standardized guidelines will be needed based on evidence accompanied by clinical trials. In addition, in-line filter applications should be considered in the clinical field depending on the patient’s condition.

Postoperative early enteral nutrition or early oral ingestion is recommended in surgical patients. In this situation, this study examined the role of parenteral nutrition in the postoperative period in patients undergoing elective surgery. The nutritional status should be assessed before surgery and in the case of malnutrition, nutritional support should be provided before surgery to obtain good results. More than 2 weeks of insufficient nutritional support after surgery may worsen the patient’s progress. Therefore, it is recommended to start nutritional care if the oral intake is not appropriate until 7 days or 5 to 7 days after surgery. Enteral nutrition is related to the quick restoration of the bowel function and reduction of infection-related complications. Therefore, enteral nutrition has priority. On the other hand, depending on the patient’s condition, it may not be possible to perform enteral nutrition, and the uniform implementation of the early enteral nutrition may be a burden to the patient. Parenteral nutrition has the advantage that it can supply nutrition without being affected by the intestinal condition, and it can be calculated to supply as much energy as required. The situation, where parenteral nutrition is required after elective surgery, could be summarized as 1) the patients who underwent nutritional therapy before surgery and could not tolerate oral intake or enteral nutrition after surgery. or 2) in the case where enteral nutrition did not satisfy 50% of the demand at 7 days after surgery, and it is judged that this situation should continue for 7 days.

Parenteral nutrition-associated liver disease (PNALD) is frequently observed in patients who require long-term parenteral nutrition. PNALD is diagnosed by clinical presentation, biochemical liver function test, long-term usage of parenteral nutrition, and negative workup for other liver diseases. Pathogenesis of PNALD is multifactorial and includes prematurity, nutritional excess, sepsis, and lack of enteral nutrition. Since PNALD was first reported more than 30 years ago, there have been various attempts to find effective treatments for PNALD. Cyclic parenteral nutrition and use of ω-3 polyunsaturated long-chain fatty acids (ω-3 PUFA) instead of ω-6 PUFA were reported worldwide as effective treatments. This article reviews the literature relating to PNALD.

Nutritional deficiency after gastrectomy is caused by anatomical and physiologic changes in the stomach. In the case of patients with gastric cancer, nausea and loss of appetite due to cancer cachexia syndrome can affect nutritional status after gastrectomy. Prognostic nutritional index based on preoperative nutritional conditions is used for prediction of postoperative outcomes including long-term survival. Generally, enteral nutrition is more effective for post-gastrectomy conditions than parenteral nutrition. In addition, specialized enteral formulas such as immunonutrition (amino acids, ω-3 fatty acids and nucleotide) seem to have benefits for gastrectomy patients, although there is still insufficient evidence. Ghrelin is a next generation agent to stimulate appetite in patients that underwent gastrectomy.

Lipids are structural components of cellular membrane and functional components exerting an important role in different metabolic pathways through regulation of cell signaling and metabolic homeostasis. Although the human body can synthesize some fatty acids, essential fatty acids (EFA) should be exogenously provided. Parenteral nutrition (PN) can be utilized to provide EFA for patients without normal gastrointestinal functions and those at risk of malnutrition. Parenteral lipids provide more energy-dense nutrition in a reduced volume and prevent EFA deficiency. However, prolonged PN with lipid emulsions is associated with metabolic complications including PN-associated liver disease. Currently available parenteral lipid emulsions provide various combinations of soybean oil, fish oil, olive oil and medium-chain triglycerides. The effects of parenteral lipid emulsions on the lipid nutrition status and PN-associated complications vary depending on the type and dosages of main oil sources used in parenteral lipid solutions. Therefore, understanding the composition, metabolism, and functional effects of lipids can be helpful in considering their clinical applications in PN.

The restricted resources on healthcare highlights the importance of clinical and cost effectiveness. The social and economic costs of chronic diseases are increasing. Home total parenteral nutrition (home TPN) for the patients with intestinal failure is a life-sustaining therapy until intestinal transplantation. An economic evaluation of home TPN has not been conducted in Korea. Three types of economic evaluations for home TPN are cost benefit analysis, cost effectiveness analysis, and cost utility analysis. Korea’s medical market is competitive due to the limited health care resources. A health care delivery system from hospital to home needs to be established under the supervision of professional Nutrition Support Team staff including the systematic policies and social recognition.

Glutamine is the most abundant amino acid, composed of more than 50 percent of free amino acid in the human body. It had been regarded as a conditional essential amino acid and its concentration is markedly reduced in critically ill patients with trauma, burn, or sepsis. From the early 1990s, many parenteral glutamine studies on critical illness have reported the benefits in mortality, infection, and length of stay. However, its clinical efficacy was based on out-of-date, smaller, single-center studies. Clinical effects of parenteral glutamine have shown no benefits or even harms in recent clinical trials and meta-analysis. Furthermore, it has challenged the hypothesis that low plasma glutamine concentration was associated with poor outcomes in critically ill patients. Although many studies showing the efficacy of glutamine have been reported, parenteral glutamine supplementation may be harmful in patients with multiorgan failure or baseline kidney dysfunction. Further studies should be conducted to identify the use of glutamine supplementation in combination with parenteral and enteral nutrition or enteral/oral nutrition alone, specific adult or pediatric patients, the appropriate time and doses for administration of glutamine, cost-benefit analysis, and the exact mechanisms of action.