Metabolic consequences of nutritional support of the cancer patient
The year 1983-1984 has been a period of evaluation and examination of efficacy of nutritional support of the cancer patient. The early observation that individual patients, unable to ingest, digest, or absorb food could be nutritionally maintained by intravenous nutrition has been repeated in every cancer center. The premature application of parenteral nutrition as an adjunct to cancer care and the results of clinical trials with small numbers of patients have initiated a reevaluation of this therapy, as a routine. The most exciting advances have come from the opportunity to utilize nutritional support as a means of investigating the basic mechanisms by which the cancer patient disposes of exogenously delivered substrate. This opportunity had been initially under-appreciated and is only now receiving the full and intensive clinical and laboratory research necessary to delineate abnormalities of metabolism that occur in the cancer-bearing host. Studies have not been performed not only in intact man, but in specific organ systems in man during nutritional support. These studies, using stable and radioactive isotopes, have given us new insight into the way that the cancer patient handles glucose and amino acids. Whether these abnormalities of metabolism are due to the cancer or are due to treatment, complications of treatment, or inherent starvation accompanying progressive cancer cachexia is being examined. Such studies should indicate whether or not therapeutic interventions in limiting substrate availability for the tumor while preserving the host are possible.