3. Nutritional Therapy for Non-end-stage Cancer Patients Undergoing Surgery Other Section
Surgical treatment for non-end-stage cancer patients includes radical surgery and palliative surgery, with an attempt to extend survival and improve quality of life. Therefore, nutritional therapy for these patients should aim at improving their tolerance to surgery, reducing the incidence of surgical complications, and lower the mortality. Severe malnutrition (under-nutrition) is an important factor affecting the clinical outcome of surgical patients; furthermore, inappropriate nutrition therapy also harms patients. Therefore, it is essential to provide appropriate nutrition therapy for preoperative patients.
3.1 Goal and Effectiveness of Nutrition Therapy for Non-end-stage Cancer Patients Undergoing Surgery
For patients undergoing major surgery with moderate or severe malnutrition (under-nutrition), nutritional therapy initiated 10–14 days before surgery can reduce the incidence of surgical complications. Among 32 RCTs, 24 have showed that enteral nutrition (EN) reduced postoperative infection-related complications, hospital stay, and hospitalization costs, while the other 8 RCTs showed negative results. For gastrointestinal cancer patients with under-nutrition, early EN reduced the incidence of postoperative infection (compared with total parenteral nutrition), but showed no such effect on patients with normal nutrition status.
The conventional 10–12-hour fasting before surgery is not conducive to the post-operative rehabilitation because it causes the body to prematurely enter into a catabolic status. Evidence has shown that liquid food intake 2–3 hours before surgery did not increase the risk of regurgitation and aspiration; therefore, the societies of anesthesiologists in many countries have rescheduled the time of preoperative fasting to 6 hours for patients undergoing elective surgery, while preoperative water deprivation only 2 hours. For patients undergoing major surgery, carbohydrate load (800 mL the night before and 400 mL two hours before surgery) did not increase the risk of aspiration. For patients undergoing colorectal surgery, hypotonic carbohydrate intake before surgery could alleviate postoperative insulin resistance, reduce skeletal muscle decomposition, and improve the tolerance; particularly, these patients have better postoperative muscle strength. For those who are not able to take oral carbohydrate preoperatively, intravenous glucose at a rate of the 5 mg/kg/min can be provided, so as to reduce insulin resistance, decrease protein consumption, and protect the myocardium.
Compared with parenteral nutrition (PN), EN is more accorded with physiological requirement and more conducive to maintaining the structure and functional integrity of the intestinal mucosal cells, with fewer complications; furthermore, it is more affordable. Therefore, EN should be preferred as long as some of the gastrointestinal digestion and absorption functions still exist. Some patients are not able to tolerate EN due to the abnormal anatomic or functional reasons of gastrointestinal tract, or EN alone is far from being sufficient to meet the metabolic demands; in these patients, PN can be a necessary approach for supporting metabolism. However, once the intestinal tract regains its normal functions, EN should be applied.
Early feeding or EN is also beneficial for patients undergoing colorectal surgery. It has been suggested that early postoperative feeding or EN (including liquid food intake within 1–2 days after surgery) does not affect colorectal anastomotic healing. However, it is unclear whether early intake of nutrients through the digestive tract has any impact on patients undergoing major gastrointestinal surgery in the upper abdomen. The current expert consensus is that the start time and the dose of the early postoperative feeding or EN should be decided according to the gastrointestinal functions and the tolerability of the patients.
Immediate or gradual withdraw of PN shows no difference in affecting blood glucose level. So far, no evidence supports that the regeneration of tumor cells is more vigorous than that of other somatic cells; meanwhile, no research suggests that such regeneration would cause harmful clinical outcomes. Therefore, it is not justifiable to giving up PN due to concerns about its supportive effect on tumor growth. For patients who are not able to obtain adequate nutrition from normal diets after discharge, EN supplements are beneficial to improve their nutrition status and reduce complications.
3.2 Indications of Nutrition Therapy for Non-end-stage Cancer Patients Undergoing Surgery
Multivariate analysis showed that undernutrition is an independent risk factor for postoperative complication, and is associated with higher mortality, longer hospital stay and high hospitalization costs. For patients undergoing major surgery with moderate or severe malnutrition (under-nutrition), nutritional therapy initiated 10–14 days before surgery can reduce the incidence of surgical complications.
For mildly undernourished patients, however, pre-operative PN is useless, and may even increase the risks of infectious complications. Also, patients without malnutrition or can obtain sufficient enteral nutrition within 7 days after surgery can not benefit from PN. Both the infection rates and the hospitalization stay are both lower in patients receiving EN than those receiving PN; however, the contraindications of EN including intestinal obstruction, hemodynamic instability, and intestinal ischemia must be ruled out. Although few case-control studies have explored the role of the combined application of EN and PN, it is commonly agreed that EN + PN can be considered for patients with the indications of nutritional therapy but their energy demands can not be met by EN alone (<60% of caloric requirements).
3.3 Method and Special Ingredients of Nutritional Therapy
Preoperative under-nutrition is more common in patients with head and neck malignancies. The high risk of postoperative infection and high incidences of postoperative anastomotic edema, obstruction and delayed gastric emptying often lead to delayed oral feeding; therefore, tube feeding nutrition should be considered, which can be carried out within 24 hours after surgery. It is safe to place feeding tube by percutaneous jejunostomy in patients undergoing major abdominal surgery; meanwhile, it is also safe to place nasojejunal feeding tube for patients undergoing pancreaticoduodenectomy. For patients undergoing proximal gastrointestinal anastomosis, EN can be provided through feeding tube with the top located in the distal end of anastomotic. For patients undergoing long-term (>4 weeks) tube feeding nutrition (e.g., patients with severe head and neck trauma), feeding tube can be placed by percutaneous endoscopic gastrostomy if no abdominal surgery is required. Considering the intestinal tolerance, it is usually feasible to carry out tube feeding nutrition at a low drip rate (e.g., l0–20 mL/h); thus, it may take 5 to 7 days to achieve a sufficient amount of nutrition intake. For perioperative patients receiving nutrition therapy, the nutritional status should be routinely re-evaluated during hospitalization; if necessary, nutritional therapy should be continued after discharge.
The energy and protein demands of cancer patients do not differ from those of healthy subjects; thus, the estimated energy demand of a bedridden patient is about 20–25 kcal/kg per day, while that of an ambulatory patient is 25–30 kcal/kg per day. If severe dysfunction of heart, liver, kidney, and/or intestines occurs, appropriate nutritional therapy should be provided. EN therapy with the formula of standard macromolecule polymer (whole protein) is applicable for most patients. A meta-analysis showed that the peri-operative application of EN containing immunomodulatory component (arginine, omega-3 fatty acids and nucleotides) in patients undergoing major surgery (e.g., laryngectomy or pharyngeal part resection) for neck tumors or those undergoing major surgery (e.g., esophageal resection, gastrectomy, or pancreaticoduodenectomy) for abdominal tumors could reduce complications and shorten hospital stay. However, for critically ill patients with systemic infections, EN containing arginine may increase the mortality. For postoperative patients without malnutrition undergoing oral feeding or EN, no sufficient evidence shows that intravenous supplement of vitamin and trace elements is feasible; however, for those with malnutrition and EN is not feasible, daily supplement of vitamins and trace elements is mandatory. Research has shown that insulin may promote synthesis metabolism in tumor patients; therefore, it may be beneficial for patients with weight loss to receive subcutaneous insulin and proper nutrition therapy.
3.4 Recommendation
A routine 12-hour preoperative fasting is not recommended for patients undergoing elective surgery without delayed gastric emptying. For surgical patients without special risk for aspiration or delayed gastric emptying, only water deprivation two hours before anesthesia and fasting 6 hours before surgery is recommended. Intravenous carbohydrates can be provided for patients who are unable to eat before surgery (Level 1).
The nutritional intake should not be interrupted for the majority of patients. Normal food intake or EN should be initiated early after surgery. Most colectomy patients can orally take liquid food (including water) a few hours after surgery (Level 1).
For patients with a risk of severe under nutrition, nutritional therapy should be provided 10 to 14 days before major surgery. For perioperative severe undernourished patients who are unable to obtain sufficient nutrition by oral feeding or EN for 5-l0 consecutive days, PN therapy should be provided (Level 1).
Tube feeding should be provided for patients who can not receive early oral nutritional therapy, especially for those who has undergone major surgeries on the head, neck, or gastrointestinal tract, experienced severe trauma, or has obvious under-nutrition. Smaller Jejunal fistula or nasojejunal tube is recommended for all patients who has received abdominal surgery and required tube feeding nutrition (Level 1).
For patients undergoing major neck surgery and abdominal surgery, the perioperative EN containing immunomodulatory components (arginine, omega-3 fatty acids, and nucleotides) can be considered (Level 1).