Early postoperative enteral nutrition improves peripheral protein kinetics in upper gastrointestinal cancer patients undergoing complete resection: a randomized trial

BACKGROUND

Patients with upper gastrointestinal (GI) tract malignancies are at risk for malnutrition and postoperative morbidity and mortality. We examined the protein kinetic effects of early enteral feeding in this population and compared it with results in patients receiving IV fluid.

METHODS

Twenty-nine patients undergoing resection of an upper GI tract malignancy were prospectively randomized to either enteral feeding starting on postoperative day (POD) 1 via a jejunostomy tube (FEED, n = 12) or IV fluid (IVF, n = 17). On POD5, all patients underwent a protein metabolic study using [3H]phenylalanine to determine forearm skeletal muscle (nmol phenylalanine/100 g/min) protein net balance. Free fatty acids (FFA, mEq/dL) and insulin levels (mU/mL) were measured.

RESULTS

Protein net balance was significantly less negative in the FEED group compared with the IVF group (-1.4 +/- 0.8 vs -5.0 +/- 1.4, p < .05). Respiratory quotient was significantly increased in patients receiving enteral feeding (0.85 +/- 0.02 vs 0.78 +/- 0.02 FEED vs IVF, p < .05). FFA levels were significantly decreased in the FEED group (0.36 +/- 0.04 vs 0.85 +/- 0.07, p < .05). Insulin levels were significantly elevated in the FEED group (19.8 +/- 4.5 vs 9.3 +/- 0.8, p < .05). Insulin levels correlated with amino acid fluxes.

CONCLUSIONS

Postoperative enteral nutrition in upper GI cancer patients results in an improvement in protein kinetic net balance and amino acid flux across peripheral tissue. In addition, insulin levels are elevated, and this elevation correlates with amino fluxes across the forearm. By improving peripheral protein kinetics, early postoperative enteral nutrition may potentially contribute to a decrease in postoperative morbidity and mortality in upper gastrointestinal cancer patients.

Effects of nandrolone propionate on experimental tumor growth and cancer cachexia

We studied the tumor host response to excessive doses of an anabolic steroid (nandrolone propionate, 2.5 mg 20 g intraperitoneally every second day for 11 days) with respect to body composition and tumor cell kinetics in MCG 101 sarcoma-bearing mice (C57BL/6J) with progressive cachexia. Although survival and food intake were not affected, a significant weight gain was observed that was essentially attributed to water retention. Net protein content was increased only to a minor extent (15%), of which only the liver accounted for a significant part of the body compartments. Hepatic protein accumulation was obviously caused by decreased protein degradation, since hepatic RNA content was unchanged. After anabolic steroid administration, reduced histochemical staining of succinate dehydrogenase was observed in skeletal muscles rich in oxidative type 1 fibers, but it was not different from that of tumor-bearing control animals, which was also confirmed by measurements of citrate synthase and cytochrome c oxidase activities in skeletal muscle and liver tissue. The anabolic steroid had no significant effect on tumor growth in terms of weight progression, energy state, polyamine synthesis rate, cell division rate, and cell cycle cytocompartments. We conclude that anabolic steroid supplementation is not therapeutically beneficial in counteracting progressive weight loss in experimental cancer.

Functional and metabolic changes during feeding in gastrointestinal cancer

The impact of feeding a hypercaloric parenteral solution on N balance, energy metabolism, and muscle strength has been investigated in cachectic patients with gastrointestinal cancer and in malnourished patients without evidence of cancer (controls). Patients were examined during 5% dextrose administration (D5W) for 2 days, followed by an infusion of a carbohydrate-based (53% carbohydrate, CB) or fat-based (55% fat, FB) diet with a constant protein intake. Diets were administered for 1 week each, in a randomized crossover design. During D5W, cancerous patients demonstrated a similar energy expenditure, but significantly lower N balance (p less than 0.005) than controls. Compared to control patients, N balance in cancerous patients was similar on the CB diet and significantly lower during the FB diet (p less than 0.025). Unlike the control patients, muscle strength and endurance tests did not improve after 2 weeks of feeding in cancerous patients. The cancerous patients differ from controls because they are hypercatabolic (especially during D5W administration), and they showed no improvement in muscle strength with 2 weeks of feeding.

Energy replacement during parenteral nutrition in surgery, sepsis and cancer

For many years, the increased nutritional requirements of surgical, septic and cancer patients were identified, but no effective therapy existed for averting their negative calorie and nitrogen balance. Parenteral nutrition offered an answer in many of these situations. However, abnormalities in liver function, ventilatory load, hyperglycemia and a disturbed metabolic homeostasis showed that in excessive amounts, glucose can behave as a relatively toxic substance. For cases with increased energy expenditure, new alternatives had to be devised in order to avoid excessive glucose intakes. One obvious possibility in these cases was to refrain from offering more than the basal caloric needs, until the patient had passed the period of acute injury, or other measures had effectively controlled the sepsis or cancer. Other options included the partial substitution of glucose by lipids or amino acids. Preliminary information suggests that this approach could lead to better nutritional outcome and survival rates, but additional studies are required.