Anorexia in cancer patients
DeWys, W.D.
Cancer Research 37(7 Pt 2): 2354-2358
1977
ISSN/ISBN: 0008-5472 PMID: 324613 Document Number: 119352
The pathophysiology of anorexia in cancer patients is poorly understood and has been difficult to study because of multiple variables which influence the clinical picture. Present understanding of food intake control in normal subjects is reviewed and attempts are made to relate it to observations in cancer patients. Hypothalamic centres can either stimulate or suppress feeding behaviour, but there is no evidence of alteration of those centres in cancer patients. Sensory input from the mouth may influence feeding behaviour. Recent studies have delineated changes in taste sensation in cancer patients which can be correlated with symptoms experienced, by the patient, extent of tumour involvement and energy intake. Sensors within the gastrointestinal tract influence the quantity of food eaten; there may be alterations in the function of those sensors in cancer patients, but no direct study of that is available. Thermostatic sensors also influence food intake; it is possible that the heat generated by tumour metabolism may tend to reduce food intake, but that also requires further study. Glucosensitive receptors exist in the brain and the liver and it is possible that the increased metabolic activity in the liver which occurs in cancer may stimulate hepatic receptors to lead to suppression of appetite; that also requires further study. Liposensitive and amino acid-sensitive receptors also influence normal food intake regulation and alterations in metabolism in the cancer patient such as amino acid imbalances may be anorexigenic. As eating behaviour is controlled by several apparently redundant cues or control mechanisms, there is probably a hierarchy among those cues; aberration of a cue high on the hierarchical scale may predominate over others. Future research should further delineate the hierarchical ranking of food intake cues and controls in normal persons and in patients with cancer.