Cancer cachexia may be an immunologic phenomenon related to increased cytokine production that occurs in response to the tumor itself or to the stress of surgery, John M. Daly, MD, said at the Society of Surgical Oncology's Annual Cancer Symposium. As such, the routine administration of preoperative total parenteral nutrition (TPN) may not be a useful strategy for all types of cancer.
Cancer cachexia may be an immunologic phenomenon related to increasedcytokine production that occurs in response to the tumor itselfor to the stress of surgery, John M. Daly, MD, said at the Societyof Surgical Oncology's Annual Cancer Symposium. As such, the routineadministration of preoperative total parenteral nutrition (TPN)may not be a useful strategy for all types of cancer.
It is unlikely that cancer cachexia is due to a nutritional deficitalone, since administration of proper nutrition does not, by itself,abrogate the symptoms, said Dr. Daly, Lewis Arterbury StimsonProfessor and Chairman, Department of Surgery, Cornell UniversityMedical College, and Surgeon-in-Chief, The New York Hospital.
Additionally, malnutrition causes immunologic changes that resemblethose in a cachectic cancer patient, Dr. Daly said in the Society'sJohn Wayne Clinical Research Lecture. For example, a decreasedand abnormal in vitro cellular response of many immune cells,such as neutrophils, natural killer (NK) cells, and lymphocytes,can be observed in both malnourished patients and those with cancercachexia.
Monoclonal antibodies to immunologic cytokines such as tumor necrosisfactor (TNF) or gamma-interferon have been shown to improve cacheticsymptoms in animal experiments, thus providing support for animmunologic role in cancer-induced malnutrition, he said.
Dr. Daly questioned the routine use of preoperative TPN in thecancer patient, because of its cost, lack of established efficacy,and associated minor infectious
the routine use of preoperative TPN in the cancer patient, becauseof its cost, lack of established efficacy, and associated minorinfectious complications. He suspects that these complicationsmay result from the immunologic effects of TPN, which has beenshown to decrease immune function in rats, down-regulating macrophageand splenocyte cell function.
Benefits of Supplemented TPN
However, when TPN is supplemented with certain amino acids, suchas glutamine dipeptide, a clear benefit has been shown in bonemarrow transplant patients in terms of decreased infections andshorter hospital stays, Dr. Daly said.
These supplements may serve as a form of "immuno-nutrition,"acting on the body to increase the immune response, thus decreasinginfections and improving wound healing, he said. The amino acidarginine, for example, has been shown to increase T-lymphocyte,macrophage, and NK cell activation; cytokine production; and thedelayed-type hypersensitivity response.
Dr. Daly said that adding amino acids or certain fatty acids toTPN may give patients a better postoperative outcome. For example,esophageal carcinoma patients undergoing esophagectomy were improvedpostoperatively when given enteral nutrition supplemented witharginine and omega 3-fatty acids (eicosapentanoic acid).
Such evidence suggests a model in which cancer-related malnutritionleads to immune suppression that could result in infection andmetastases.
Supplemented enteral nutrition may have a role in improving theimmune response under such conditions, Dr. Daly said. However,for many cancers, preoperative TPN does not seem to be indicated,considering the risk of complications. He believes that its routineuse should be avoided, and preoperative supplemented TPN shouldbe used only in patients with severe malnutrition or in thoseundergoing bone marrow transplantation.