Tumor-host responses to various nutritional feeding procedures in rats.

Parenteral and enteral nutrition are being used as adjuncts to cancer therapy. A liquid diet formulation containing a 27% solution of glucose and 3.9% crystalline amino acids with electrolytes and vitamins was given continuously for a week via parenteral (iv), and via intragastric (ig) routes and also was given ad libitum via the oral or per os (po) route to groups of Buffalo rats with and without a Morris No. 7777 transplantable hepatoma to find out how these feeding procedures affect tumor-host interactions. Other groups of rats with and without the hepatoma were given solid food ad libitum. The following parameters were examined: mortality, carcass and organ weights, body and tumor growth, nitrogen balance, energy intake, fluid balance, urinalysis, hematology values, and serum protein levels. The results are considered with respect to the influence of the tumor on the host and the influence of the feeding procedure on the animal with and without a tumor. The presence of the hepatoma was associated with: higher mortality, a decrease in carcass mass, leucocytosis, anemia, a decrease in serum IgG, transferrin and albumin, and an increase in serum alpha fetoprotein. The iv and ig feeding procedures alone resulted in some mortality which was exacerbated by the presence of the tumor. Mortality was especially high in the tumorous rats on the ig feeding procedure. The degree of positive nitrogen balance and carcass mass was similar in non-tumorous rats fed the same liquid diet formula when given iv, ig, or po. Tumorous rats fed the liquid diet ad libitum showed anorexia and a significantly lower nitrogen balance. The iv and ig feeding of tumorous rats at a level which was well above those of the tumorous rats given solid or liquid diet ad libitum maintained the same degree of positive nitrogen balance as non-tumorous rats. Even though the iv feeding of tumorous rats maintained about the same degree of positive nitrogen balance as non-tumorous rats, these tumorous rats still suffered loss of carcass mass. It appears that the large rapidly growing hepatoma has priority for available nutrition over the host. It is further suggested that the rapidly growing hepatoma places an ever increasing demand on the available nutrients. Thus, a point is eventually reached where even supplemental nutritional support can no longer meet the needs of the growing hepatoma and the host.