Total Parenteral Nutrition and Tumor Metastases M. H. TOROSIAN, ROBERT B. DONOWAY Surgery 109:597–601, 1991

Abstract

The authors studied the effect of total parenteral nutrition on primary tumor growth and spontaneous prostate adenocarcinoma (PA III) implants. Thirty‐four immature female Lobund/Wistar rats were inoculated subcutaneously with fragments of PA III tumor cells. This is a prostate adenocarcinoma that spontaneously metastasizes to the lungs and lymph nodes. After tumor inoculation all animals received a standard protein diet for 18 days, followed by a protein‐delayed diet from day 18 to day 25. On day 25 all animals underwent superior vena cava cannulation. Subsequently animals were randomized to receive one of five regimens: (1) 3% amino acid/9% dextrose/3.6% lipids parenterally, (2) 3% amino acids/18% dextrose parenterally, (3) 18% dextrose parenterally, (4) protein depleted food ad libitum enterally, (5) standard protein diet ad libitum enterally. All parenteral nutrient regimens were isocaloric (175 calories/ kg per day) and those containing amino acids were iso‐nitrogenous (1.16 g of nitrogen/kg per day). Tumor volume and doubling time were determined daily from day 25 to 35. Animals were killed 35 days later, the implanted tumors were completely excised, and carcass weights were determined. The lungs and trachea were excised for quantitative analyses of pulmonary metastases.Animals given parenteral amino acids/dextrose/lipid, parenteral amino acids/dextrose, or central standard protein diet weighed significantly more at the time of death than did animals in the other two groups. Primary tumor volumes and tumor weights were greater in animals receiving either parenteral amino acids/dextrose/ lipid or enteral standard protein diet. Animals given either parenteral dextrose alone or protein‐depleted food enterally had the smallest primary tumors, as determined by volume and weight measurements. It was also noted that tumor doubling time correlated inversely with tumor volume and weight; thus, the longest tumor doubling time occurred in the animals with the smallest primary tumor volume and weight. The number of pulmonary metastases was greatest in animals receiving either the mixed substrate parenteral diet (amino acids/dextrose/ lipid) or the enteral standard protein diet. A significant increase in metastases occurred in animals given parenteral mixed substrate diet compared with animals receiving parenteral amino acids/dextrose or dextrose alone. Compared with the protein‐depleted group, animals given a standard protein diet enterally showed a significantly greater number of large tumor metastases.