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.

Enteral nutrition (EN) formulas are foods that are used to improve the nutritional status of patients and these foods’ safety and quality must be ensured. Therefore, EN formulas in other countries are managed differently from that of general foods. We investigated the direction of development of the relevant laws regulations and guidelines pertaining to EN formulas and we compared these laws regulations and guidelines from different countries, including Korea. The United States and Europe manage EN formulas as foods, but they are managed differently compared to general foods because of separate laws or programs pertaining to EN foods. In addition, the use of the formulas does not necessarily require a prescription, but when used by prescription, then medical insurance covers them. In Japan, there are two types of EN formulas, food and drug, and there are differences for their management and insurance coverage. In the case of Korea, EN formulas are classified as food and drug, and different management and insurance are applied in each case, which inhibits their systematic management and industrial development. Integration of a management system and establishment of a legal foundation is necessary for the systematic management and development of EN formula in Korea.

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.

The nutritional support of acutely ill patients is very important and early enteral nutrition is recommended. Feeding via the nasogastric route is used widely for its ease of access if the patient cannot maintain volitional food intake. If the position of the tip or side holes of the nasogastric tube (NGT) is above the gastroesophageal junction, there is the possibility of retention and solidification of the administered enteral feeding formula in the esophagus. Therefore, the tip of the NGT should be checked carefully; a chest radiograph to confirm its position can be considered, especially in patients with a higher risk of aspiration and gastroesophageal reflux. In addition, careful consideration of the risk factors that can trigger esophageal obstruction is required when feeding patients in the intensive care unit. This paper describes two unusual cases of esophageal obstruction caused by the solidification of residue of an enteral feeding formula.

Patients with chronic liver disease have a high risk to malnutrition. Proper nutrition should be provided through a proper nutritional assessment. Enteral nutrition is recommended as a nutritional supplement because it maintains the intestinal mucosa, reduces infectious complications, is less costly than parenteral nutrition, and is more physiological to use intestine. The purpose of this review is to define the nutritional deficiencies of patients with liver disease and to show the indications for enteral nutrition and to validate the efficacy of enteral nutrition. According to the various guidelines and researches, enteral nutrition is used as a solution to the nutritional problems caused by patients with liver disease. The optimal enteral formula will be selected on the nutritional problems. It is expected that the enteral nutrition will reduce especially postoperative complications, intraperitoneal complications, pneumonia, and wound infection. The enteral nutrition for patients with chronic liver disease should be actively implemented.

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.