Effect of postoperative total parenteral nutrition (TPN) as an adjunct to gastrectomy for advanced gastric carcinoma

State of the scientific evidence and recommendations for the management of older patients with gastric cancer

Gastric cancer is one of the most frequent and deadly tumours worldwide. However, the evidence that currently exists for the treatment of older adults is limited and is derived mainly from clinical trials in which older patients are poorly represented. In this article, a group of experts selected from the Oncogeriatrics Section of the Spanish Society of Medical Oncology (SEOM), the Spanish Group for the Treatment of Digestive Tumours (TTD), and the Spanish Multidisciplinary Group on Digestive Cancer (GEMCAD) reviews the existing scientific evidence for older patients (≥65 years old) with gastric cancer and establishes a series of recommendations that allow optimization of management during all phases of the disease. Geriatric assessment (GA) and a multidisciplinary approach should be fundamental parts of the process. In early stages, endoscopic submucosal resection or laparoscopic gastrectomy is recommended depending on the stage. In locally advanced stage, the tolerability of triplet regimens has been established; however, as in the metastatic stage, platinum- and fluoropyrimidine-based regimens with the possibility of lower dose intensity are recommended resulting in similar efficacy. Likewise, the administration of trastuzumab, ramucirumab and immunotherapy for unresectable metastatic or locally advanced disease is safe. Supportive treatment acquires special importance in a population with different life expectancies than at a younger age. It is essential to consider the general state of the patient and the psychosocial dimension.

Nutrition support in hospitalised adults at nutritional risk

BACKGROUND

The prevalence of disease-related malnutrition in Western European hospitals is estimated to be about 30%. There is no consensus whether poor nutritional status causes poorer clinical outcome or if it is merely associated with it. The intention with all forms of nutrition support is to increase uptake of essential nutrients and improve clinical outcome. Previous reviews have shown conflicting results with regard to the effects of nutrition support.

OBJECTIVES

To assess the benefits and harms of nutrition support versus no intervention, treatment as usual, or placebo in hospitalised adults at nutritional risk.

SEARCH METHODS

We searched Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE (Ovid SP), Embase (Ovid SP), LILACS (BIREME), and Science Citation Index Expanded (Web of Science). We also searched the World Health Organization International Clinical Trials Registry Platform (www.who.int/ictrp); ClinicalTrials.gov; Turning Research Into Practice (TRIP); Google Scholar; and BIOSIS, as well as relevant bibliographies of review articles and personal files. All searches are current to February 2016.

SELECTION CRITERIA

We include randomised clinical trials, irrespective of publication type, publication date, and language, comparing nutrition support versus control in hospitalised adults at nutritional risk. We exclude trials assessing non-standard nutrition support.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane and the Cochrane Hepato-Biliary Group. We used trial domains to assess the risks of systematic error (bias). We conducted Trial Sequential Analyses to control for the risks of random errors. We considered a P value of 0.025 or less as statistically significant. We used GRADE methodology. Our primary outcomes were all-cause mortality, serious adverse events, and health-related quality of life.

MAIN RESULTS

We included 244 randomised clinical trials with 28,619 participants that met our inclusion criteria. We considered all trials to be at high risk of bias. Two trials accounted for one-third of all included participants. The included participants were heterogenous with regard to disease (20 different medical specialties). The experimental interventions were parenteral nutrition (86 trials); enteral nutrition (tube-feeding) (80 trials); oral nutrition support (55 trials); mixed experimental intervention (12 trials); general nutrition support (9 trials); and fortified food (2 trials). The control interventions were treatment as usual (122 trials); no intervention (107 trials); and placebo (15 trials). In 204/244 trials, the intervention lasted three days or more.We found no evidence of a difference between nutrition support and control for short-term mortality (end of intervention). The absolute risk was 8.3% across the control groups compared with 7.8% (7.1% to 8.5%) in the intervention groups, based on the risk ratio (RR) of 0.94 (95% confidence interval (CI) 0.86 to 1.03, P = 0.16, 21,758 participants, 114 trials, low quality of evidence). We found no evidence of a difference between nutrition support and control for long-term mortality (maximum follow-up). The absolute risk was 13.2% in the control group compared with 12.2% (11.6% to 13%) following nutritional interventions based on a RR of 0.93 (95% CI 0.88 to 0.99, P = 0.03, 23,170 participants, 127 trials, low quality of evidence). Trial Sequential Analysis showed we only had enough information to assess a risk ratio reduction of approximately 10% or more. A risk ratio reduction of 10% or more could be rejected.We found no evidence of a difference between nutrition support and control for short-term serious adverse events. The absolute risk was 9.9% in the control groups versus 9.2% (8.5% to 10%), with nutrition based on the RR of 0.93 (95% CI 0.86 to 1.01, P = 0.07, 22,087 participants, 123 trials, low quality of evidence). At long-term follow-up, the reduction in the risk of serious adverse events was 1.5%, from 15.2% in control groups to 13.8% (12.9% to 14.7%) following nutritional support (RR 0.91, 95% CI 0.85 to 0.97, P = 0.004, 23,413 participants, 137 trials, low quality of evidence). However, the Trial Sequential Analysis showed we only had enough information to assess a risk ratio reduction of approximately 10% or more. A risk ratio reduction of 10% or more could be rejected.Trial Sequential Analysis of enteral nutrition alone showed that enteral nutrition might reduce serious adverse events at maximum follow-up in people with different diseases. We could find no beneficial effect of oral nutrition support or parenteral nutrition support on all-cause mortality and serious adverse events in any subgroup.Only 16 trials assessed health-related quality of life. We performed a meta-analysis of two trials reporting EuroQoL utility score at long-term follow-up and found very low quality of evidence for effects of nutritional support on quality of life (mean difference (MD) -0.01, 95% CI -0.03 to 0.01; 3961 participants, two trials). Trial Sequential Analyses showed that we did not have enough information to confirm or reject clinically relevant intervention effects on quality of life.Nutrition support may increase weight at short-term follow-up (MD 1.32 kg, 95% CI 0.65 to 2.00, 5445 participants, 68 trials, very low quality of evidence).

AUTHORS' CONCLUSIONS

There is low-quality evidence for the effects of nutrition support on mortality and serious adverse events. Based on the results of our review, it does not appear to lead to a risk ratio reduction of approximately 10% or more in either all-cause mortality or serious adverse events at short-term and long-term follow-up.There is very low-quality evidence for an increase in weight with nutrition support at the end of treatment in hospitalised adults determined to be at nutritional risk. The effects of nutrition support on all remaining outcomes are unclear.Despite the clinically heterogenous population and the high risk of bias of all included trials, our analyses showed limited signs of statistical heterogeneity. Further trials may be warranted, assessing enteral nutrition (tube-feeding) for different patient groups. Future trials ought to be conducted with low risks of systematic errors and low risks of random errors, and they also ought to assess health-related quality of life.

From means to ends: artificial nutrition and hydration

The withdrawal, withholding, or implementation of life-sustaining treatments such as artificial nutrition and hydration challenge nurses on a daily basis. To meet these challenges, nurses need the composite skills of moral and ethical discernment, practical wisdom and a knowledge base that justifies reasoning and actions that support patient and family decision making. Nurses' moral knowledge develops through experiential learning, didactic learning, and deliberation of ethical principles that merge with moral intuition, ethical codes, and moral theories. Only when a nurse becomes skilled and confident in gathering empiric and ethical knowledge can he or she fully act as a moral agent in assisting families faced with making highly emotional decisions regarding the provision, withholding, or withdrawal of artificial nutrition and hydration.

Do Data Support Nutrition Support? Part I: Intravenous Nutrition

Intravenous (parenteral) nutrition has been advocated widely as adjunctive care in patients with a variety of underlying diseases. However, the enthusiasm for this therapeutic intervention was based largely on expert opinion. Because the best way to assess the efficacy of any treatment is to test it in a randomized controlled trial, this review will focus on data that was derived from such studies. Using established search strategies, randomized controlled trials were sought that compared one of two forms of intravenous nutrition: parenteral nutrition (nitrogen and >or=10 kcal/kg/day of non-protein calories for >or=5 days) or protein-sparing therapy (nitrogen and fewer non-protein calories) with no type of artificial nutrition beyond regular food and/or standard (5%) dextrose. The randomized controlled trials were stratified by the underlying disease state. The clinical outcomes of interest were mortality, morbidity (total/infectious complications), and/or duration of hospitalization. More than 100 randomized controlled trials failed for the most part to demonstrate that intravenous nutrition had any effect on clinical outcome. There were a few exceptions. In patients undergoing attempted curative surgery for upper gastrointestinal cancer, the use of preoperative parenteral nutrition seemed to reduce the incidence of major postoperative complications. However, this benefit was only found in low-quality randomized controlled trials. Findings conflict regarding the use of parenteral nutrition in patients with acute pancreatitis or undergoing bone marrow transplantation. Parenteral nutrition was harmful when provided to patients undergoing radiation or chemotherapy for cancer. Although no randomized controlled trials exist, it is assumed that parenteral nutrition is useful in patients with an inadequate gastrointestinal tract ("short gut"). Thus, for the most part, randomized controlled trials comparing intravenous nutrition to no artificial nutrition have not shown that this medical intervention is of benefit.

Nutrition Society Symposium on ‘End points in clinical nutrition trials’ Death, morbidity and economics are the only end points for trials

In order to determine whether surrogate markers predict clinical outcome, randomized controlled trials (RCT) of nutrition supportv. no nutrition support that have reported at least one clinical outcome (mortality, infections, total complications, or duration of hospitalization) and at least one nutritional outcome (energy or protein intake, weight gain, N balance, albumin, prealbumin, transferrin, three anthropometric measures, skin testing, lymphocyte count) were assessed for concordance. If changes in nutritional markers predict clinical outcome, changes in both outcomes should go in the same direction. Concordance is defined as both outcomes changing in the same direction or both outcomes showing no difference. Discordance is defined as one outcome changing and the other not (partial) or both outcomes changing in opposite directions (complete). Ninety-nine RCT were identified, of which most were underpowered to see statistically significant changes, especially in clinical outcomes. Thus, the results were analysed only in relation to the direction of the respective changes in outcomes. Forty-eight comparisons (4×12) were made. The rates of concordance were ≤50% in forty-one of forty-eight comparisons; the rate was never >75%. A complete discordance rate of ≥25% was present in forty-three (≥50% in thirteen) of the forty-eight comparisons. The discordance was usually a result of the nutritional outcome being better than the clinical outcome. Changes in nutritional markers do not predict clinical outcomes. Before adopting any surrogate marker as an end point for a clinical trial, it has to be known that improving it will result in patient benefit.

Nutrition in the perioperative patient

The association of malnutrition with surgical morbidity and mortality is well recognized. The question of whether this relationship is causal or simply an association in sick patients has been hotly debated. The field of nutrition support has grown out of the belief that correcting malnutrition will modify associated risks for poor outcome. It has been easier to substantiate this belief in some clinical situations than in others. The evidence for nutrition support during the perioperative period is reviewed and recommendations are made about where nutrition support is most useful and where it may be counterproductive. Some of the important unanswered questions about perioperative nutrition support are raised.

AGA technical review on parenteral nutrition

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. The paper was approved by the Committee on September 13, 2001, and by the AGA Governing Board on May 18, 2001.

Parenteral nutrition in the critically-ill patient: more harm than good?

While many studies have reported that providing parenteral nutrition (PN) can change nutritional outcomes, there are limited data that demonstrate that PN influences clinically-important end points in critically-ill patients. The purpose of the present paper is to systematically review and critically appraise the literature to examine the relationship between PN and morbidity and mortality in the critically-ill patient. Studies comparing enteral nutrition (EN) with PN and studies comparing PN with no PN were reviewed. The results suggest that EN is associated with reduced infectious complications in some critically-ill subgroups. PN, on the other hand, is associated with increased morbidity and mortality in critically-ill patients. When nutritional support is indicated, EN should be used preferentially over PN. Further studies are needed to define the optimal timing and composition of PN in patients not tolerating sufficient EN. Strategies to optimize EN delivery and minimize PN utilization in critically-ill patients are indicated.

Perioperative total parenteral nutrition in malnourished, gastrointestinal cancer patients: a randomized, clinical trial

BACKGROUND

Clinical trials investigating the potential benefits of perioperative total parenteral nutrition (TPN) for reducing the risk of surgery in malnourished cancer patients have yielded controversial results.

METHODS

Ninety elective surgical patients with gastric or colorectal tumors and weight loss of 10% or more of usual body weight were randomly assigned to 10 days of preoperative and 9 days of postoperative nutrition vs a simple control group. The daily per kilogram body weight TPN regimen included 34.6 +/- 6.3 kcal nonprotein and 0.25 +/- 0.04 g nitrogen per kilogram in a volume of 42.6 +/- 7.3 mL of fluid. The glucose-to-fat calorie ratio was 70:30. Control patients did not receive preoperative nutrition but received 940 kcal nonprotein plus 85 g amino acids postoperatively.

RESULTS

Complications occurred in 37% of the patients receiving TPN vs 57% of the control patients (p = .03). Noninfectious complications mainly accounted for this difference, which was 12% vs 34%, respectively (p = .02). Mortality occurred in only 5 of the control group patients (p = .05). The total length of hospitalization for TPN patients was longer than for control (p = .00), whereas the length of postoperative stay in the two groups did not differ significantly.

CONCLUSIONS

This study shows that 10 days of preoperative TPN that is continued postoperatively is able to reduce the complication rate by approximately one third and to prevent mortality in severely malnourished patients with gastrointestinal cancer.

[In which patients and for which procedures has the efficacy of postoperative artificial nutrition be proven?]

This study reviewed 19 prospective studies for the incidence of postoperative nutritional support on outcome in elective surgery. It compared enteral and parenteral nutrition initiated no more than three days preoperatively or postoperatively and prolonged maximally for one month, to a simple infusion of glucose or saline. As all studies had methodological weaknesses, concerning mainly the sample size, it is impossible to propose relevant recommendations. Nevertheless, among the 11 studies on total parenteral nutritional support (nitrogen and caloric supply with carbohydrates and/or lipids), three of them produced valuable results. As the available data do not show any beneficial effect, a routine postoperative nutritional support cannot be recommended, even in patients at high risk of postoperative complications. However for the latter a possible benefit cannot be totally excluded in some of them. When an alimentation per mouth cannot be started during the 8 to 10 days after surgery, an artificial nutritional support becomes mandatory.

[Caloric and nitrogen intake during pre- and post-operative periods. method and duration]

Preoperative nutritional support is analysed from 7 prospective studies. Clinical benefits from nutrient intake and duration are not demonstrable. In one study, preoperative long-chain triglycerides infusions are associated with more postoperative complications. Postoperative nutrition is analysed from 20 articles. No one considers the clinical benefit with regard to quantitative and qualitative intakes.

Nutrition support in patients with cancer: what do the data really show?

Although more than 70 prospective randomized controlled trials have evaluated the use of nutrition support in patients with cancer, the indications for nutrition therapy in this patient population remain controversial. We reviewed the published prospective randomized controlled trials that evaluated clinically important endpoints (morbidity, mortality, and duration of hospitalization). Many trials had serious shortcomings in study design that limit the ability to draw definitive conclusions from the data. In general, the data failed to demonstrate the clinical efficacy of providing nutrition support to most patients with cancer. Therefore, the indications for using nutrition therapy should be the same as those for patients with benign disease.

Protein and amino acid metabolism in cancer cachexia: investigative techniques and therapeutic interventions

Cancer cachexia is a complex syndrome characterized primarily by diminished nutrient intake and progressive tissue depletion that is manifest clinically as anorexia and host weight loss. The gradual loss of host protein stores is central to this process. This review outlines the techniques that have been used to evaluate human amino acid metabolism, their application in patients with cancer cachexia, and possible therapeutic interventions designed to overcome alterations in host protein and amino acid metabolism associated with malignant cachexia. The techniques of nitrogen balance and 3-methylhistidine excretion provide indirect estimates of overall nitrogen metabolism and skeletal muscle myofibrillar protein breakdown. Measurement of circulating amino acid concentrations, particularly when combined with assessment of arterial-venous differences and regional amino acid balance allows for investigation of interorgan amino acid metabolism. One of the most significant advances in in vivo amino acid metabolic research has been the development of labeled amino acid tracer studies to evaluate whole body and regional amino acid kinetics. The use of stable and unstable amino acid isotopes in these techniques is reviewed in detail. Virtually all of these techniques have now been employed in the evaluation of human cancer cachexia. The results of studies evaluating amino acid concentrations, regional amino acid balance, and 3-methylhistidine excretion are summarized. The use of regional and whole body kinetic studies in cancer cachexia are reviewed extensively. Most investigators have observed increased rates of whole body protein turnover, synthesis, and catabolism in both weight-stable and weight-losing cancer patients. Some studies have suggested a relationship between the extent of disease and the degree of aberration in amino acid kinetic parameters. Investigators have attempted to reverse some of these alterations by provision of substrate (nutritional support) or administration of specific pharmacologic or anabolic agents such as hydrazine sulfate, insulin, growth hormone, and beta-2 agonists. The role of total parenteral nutrition (TPN) in cancer and its effects on protein and amino acid kinetics and tumor growth are addressed. The possible benefits of specific amino acid nutritional formulations with increased branched chain amino acids, arginine, and glutamine are reviewed. Although many of these approaches appear promising, significant impact on clinically definable parameters remains to be demonstrated. A better understanding of the underlying protein catabolic mechanisms of cancer cachexia will likely lead to more effective therapies to reverse the protein calorie malnutrition associated with cancer cachexia.

Nutrition and malignant disease: implications for surgical practice

Malignant disease is often associated with weight loss and malnutrition. Nutritional support is frequently provided to patients with cancer in an attempt to improve nutritional status and reverse weight loss, with the aim of reducing morbidity and mortality rates. This review evaluates the effect of supplemental nutrition on morbidity and mortality in patients with malignancy undergoing treatment with surgery, chemotherapy or radiotherapy. It also assesses the effect nutritional supplementation has on host defence mechanisms and how nutrients affect tumour cell growth. The evidence suggests that perioperative nutritional support, if given for at least 10 days, reduces morbidity and mortality in patients with biochemical evidence of severe malnutrition, manifest as a low serum albumin concentration and excessive weight loss. In contrast, there is no evidence that parenteral nutritional support benefits patients undergoing chemotherapy or radiotherapy, in terms of either an increased tumour response rate or prolongation of survival. Current research on malignant disease is highlighting the role of specific nutrients (amino acids, essential fatty acids and polyribonucleotides) as key regulators of both anticancer host defence mechanisms and the control of nitrogen metabolism and tumour growth. Arginine, essential fatty acids and ribonucleotides have all been demonstrated to stimulate antitumour host defence mechanisms and some also modulate tumour cell metabolism. Dietary manipulation offers exciting possibilities for the innovative management of malignant disease.

Perioperative nutritional support

In selected malnourished patients, perioperative nutritional support can decrease the morbidity and mortality rates associated with major surgical procedures. Preoperative nutritional support should be delivered via the gastrointestinal tract whenever feasible, generally in the form of enteral diets, which can be given via a feeding tube or as a dietary supplement. Patients with a functional gut who cannot eat because of anorexia or upper gastrointestinal tract obstruction are candidates for preoperative tube feedings. Total parenteral nutrition should be the mainstay of nutritional support when the gastrointestinal tract cannot be used adequately. An improvement in nutritional indices (e.g., serum transferrin, lymphocyte count) may be associated with decreased perioperative morbidity, although the strength of this relation is not clear. In the absence of improvement in such indices, the duration of nutritional support required to decrease operative morbidity is unknown. Postoperatively, enteral tube feedings (delivered via a nasojejunal tube or feeding jejunostomy) should be provided to all preoperatively malnourished patients with a functional gastrointestinal tract who are unable to consume adequate calories orally. Postoperative TPN should be reserved for malnourished patients with a nonfunctional gut or for patients who develop a postoperative complication that precludes enteral feeding. Current nutritional formulas have often neglected the metabolic and nutritional requirements of the intestinal tract. In the future, the combined use of specific nutrients and growth factors may improve nutritional rehabilitation in catabolic patients.

Nutritional support in surgical practice: Part I

Critical evaluation of the therapeutic benefit gained from provision of nutritional support requires knowledge regarding the nutritional status of those to whom it was given. The apparent effect of giving parenteral nutrition or enteral nutrition depends not only on how much and how well it is given, but also on how depleted the recipient is. Thus, nutritional assessment requires close examination before proceeding to assess the efficacy and potential benefits of the remedial measures of parenteral nutrition or enteral nutrition. Although preoperative malnutrition is associated with a poor operative outcome, there appears to be no consensus as to whether perioperative nutritional support can reduce postoperative complications to the level occurring in well-nourished patients undergoing similar procedures. This is partly because reports evaluating the effect of perioperative nutritional support on postoperative outcome vary widely as to numbers of patients studied, primary diagnoses, and the duration and quality of perioperative nutritional support. In Part I, these issues are explored in patients who are undergoing operations for cancer, trauma, or burns. Enteral nutrition appears to be as effective as parenteral nutrition in improving operative outcome, as compared with ad libitum oral nutrition. Postoperative enteral nutrition and parenteral nutrition are equally effective in reducing postoperative complications.

Preoperative nutritional assessment to predict postoperative complication in gastric cancer patients

The correlation between preoperative nutritional parameters and postoperative complications in 440 patients with gastric cancer were analyzed. All the nutritional parameters reflected a significant deterioration as the stages of cancer progressed, and the frequency of postoperative complications was highest in patients with stage IV gastric cancer. The incidence of anastomotic leaks was increased in patients undergoing total gastrectomy with no relation to the clinical stage or nutritional status. However, there was a close relationship between nutritional status and immunocompetence, lung complications, and infection. The nutritional indices which reliably predicted preoperatively the nutritional status of cancer patients were the serum protein concentrations including the serum albumin (Alb) and prealbumin (PA). The indices predicting postoperative complications were the Alb, PA, and total lymphocyte count. These results suggest that preoperative nutritional assessment can be beneficial for the prediction of postoperative complications.

Complications of abdominal operations for malignant disease

The incidence of morbidity and mortality in 365 consecutive patients with a mean age of 60 years who underwent intraabdominal operation for a variety of cancers involving different organ systems over a recent 2-year period was analyzed. The primary tumor sites were the esophagus (21 patients), gastroduodenum (33 patients), liver and gallbladder (6 patients), pancreas (15 patients), colorectum (101 patients), lymphoproliferative disorders (35 patients), abdominal carcinomatosis (45 patients), genitourinary and gynecologic systems (94 patients), and other sites (15 patients). One hundred eighty-two patients (49 percent) had 1 or more complications (grouped as gastrointestinal, septic, cardiopulmonary, and nonseptic) and 47 patients died (12.9 percent). The 145 patients who underwent a palliative procedure had the highest morbidity and mortality rates (41 percent and 21 percent, respectively). In the 168 patients who had curative resection, the morbidity and mortality rates were 39 percent and 9 percent, respectively, and in 51 patients with a diagnostic laparotomy, 20 percent and 4 percent, respectively. Age was not a contributory factor. The 177 malnourished patients had a significantly higher incidence of complications (72 percent) and postoperative death (23 percent) than the well-nourished patients (29 percent and 4 percent, respectively; p less than 0.001). These differences also existed with each form of complication. Of those patients without complications, the majority resumed consuming 60 percent of their caloric requirements by postoperative day 9. In the majority of patients with complications, resumption of adequate oral intake occurred by postoperative day 20.

Optimal nutritional indexes in cancer patients

This paper reviews various parameters that are used to assess the nutritional and functional status of cancer patients. Available information shows that the nutritional status of cancer patients is correlated with their overall prognosis and outcome. However, little information exists concerning the use of nutritional indexes to evaluate the effectiveness of nutritional rehabilitation of cancer patients. It is emphasized that we should concentrate on developing nutritional parameters to assess the functional improvement of patients rather than their body structure and composition.

Influence of nutritional status on the resumption of adequate food intake in patients recovering from colorectal cancer operations

The influence of nutritional status on the resumption of adequate food intake in 101 patients recovering from colorectal cancer operation was examined. Two thirds of these patients were well-nourished; the others were malnourished. Malnutrition criteria were serum albumin of less than 3.5 gm per dl plus any two of the following four factors: recent weight loss greater than 10 per cent or weight for height, mid-arm circumference, and triceps skinfold thickness lower than the tenth percentile. Over half of the well-nourished patients were eating 60 per cent or greater of their caloric requirements by the tenth postoperative day, whereas only one quarter of the malnourished patients had attained this intake. the morbidity and mortality in 33 malnourished patients was 52 and 12 per cent, respectively, compared with 31 and 6 per cent (p less than 0.01) in 68 nourished patients. The duration of postoperative functional starvation in malnourished patients without complications increased to an average of 22 days following a complication and was further prolonged after a complication. Age or operative procedure (curative or palliative) did not influence complication rate. Our data suggest that postoperative nutritional support as either TPN or enteral feeding using an elemental diet is indicated in malnourished patients and in well-nourished patients immediately following a complication requiring therapeutic intervention.

Value of nutritional support in adult cancer patients

Both the presence of cancer and oncologic therapy cause metabolic alterations that may decrease the ability of the host to maintain anabolism. Nutritional support, properly administered, will replenish lean body mass, visceral proteins, and immunocompetence in human beings and experimental animals with small to modest tumor burdens. To date, stimulation of tumor growth by intravenous hyperalimentation in malnourished patients has not been documented scientifically. The exact role of intravenous hyperalimentation, in combination with chemotherapy or radiation therapy, is controversial, whereas the role of nutritional support for the malnourished surgical patient is more firmly established.

Nutritional support: how much for how much?

Although malnutrition is associated with poor clinical outcome, it cannot be inferred that better nutrition will improve clinical outcome. Efficacy of a proposed regimen is best established by prospective, randomised, controlled trials. Cost effectiveness is only an issue if efficacy exists. Patients with long term temporary, or permanent, inadequate bowel syndrome are candidates for parenteral nutrition. Most of the prospective, randomised, controlled trials testing the value of nutritional support in other diseases, however, have failed to show that this treatment has a beneficial clinical effect. Areas where these trials have shown a possible clinical benefit include the perioperative care of patients with upper gastrointestinal cancer, elemental diet treatment of Crohn's disease, and branched chain amino acid infusions in hepatic encephalopathy. Even in these instances, it is not clear that such treatment will prove to be cost effective (compared with other currently available treatments).

Decreased interleukin-2 production in patients with gastrointestinal cancer

Mitogen-stimulated basal and maximal interleukin-2 production has been measured in 60 control subjects and 45 patients with gastrointestinal cancer (14 localized and 31 advanced). Peripheral blood T cell subsets in these subjects were also measured. In patients with advanced gastrointestinal cancer interleukin-2 production (mean +/- s.e.m. units/ml) is impaired when compared with that of control subjects (26.5 +/- 7 versus 61.1 +/- 9, P less than 0.0001) or patients with localized cancer (26.5 +/- 7 versus 59.4 +/- 13, P less than 0.02). This cannot be restored to normal by in vitro irradiation of the lymphocytes, suggesting that the impaired function is not due to IL-2 suppressor cells. Using monoclonal antibodies the percentages of T cell subsets were similar in all groups and we therefore conclude that the reduced production of IL-2 in these patients is due to deficient helper T cell function. These results provide a rational basis for the administration of exogenous IL-2 in the future management of patients with advanced gastrointestinal cancer.

Preoperative identification of the surgical cancer patient in need of postoperative supportive total parenteral nutrition

In the absence of specific therapy, nutrition was the mainstay of medicine in ancient times. Because of the current emphasis on modern treatment modalities in the fight against cancer, the provision of adequate nutrition is frequently overlooked. Because of the inconsistent results obtained from randomized trials of total parenteral nutrition (TPN) in cancer patients undergoing chemotherapy and radiation therapy, ambivalence about the usefulness of TPN as an adjunct to cancer therapy (particularly as it pertains to surgical patients) is further confused by the lack of appropriate criteria for the use of TPN postoperatively. The incidence of malnutrition in relation to certain cancer types is high. Malnutrition is associated with a higher incidence of both postoperative complications and mortality when compared to the well nourished patient. Consequently, preoperative criteria were developed to identify that group of cancer patients requiring abdominal operation who are at high risk and in whom planned nutritional support should be initiated postoperatively. Use of these criteria provides a rational basis for the use of TPN postoperatively.