[Pharmacological therapy of cancer anorexia-cachexia]

Abstract

Anorexia is one of the most common symptoms of patients with advanced cancer and it presents as loss of appetite due to satiety. On the other hand, cachexia is described in those patients with unwanted weight loss. Cancerous processes produce an energy unbalance by decreased food intake and increased catabolism, resulting in a clearly negative balance. Several factors determining cachexia are observed, from metabolic unbalances produced by tumoral products and endocrine impairments or the inflammatory response produced by cytokines, all of them leading to higher lipolysis, loss of muscle protein, and anorexia. Besides, causes of anorexia are multiple, from chemotherapy agents, radiotherapy, or immunotherapy, which may produce different degrees of nausea, vomiting, diarrhea, and also leading to impairments of taste and smell, to obstruction of the digestive tract, pain, depression, constipation, etc. From the knowledge of the different mechanisms producing the anorexia-cachexia syndrome, hypercaloric diets for artificial nutrition have been studied with varying success, and different drugs with a positive effect on appetite gain such as progestogens, steroids, and with lesser clinical evidence cannabinoids, cyproheptadine, mirtazapine (antidepressant), and olanzapine (antipsychotic). Other drugs have been studied because of their anti-inflammatory properties, anti-cytokine, such as melatonin, polyunsaturated omega-3 fatty acids, pentoxifylline, and thalidomide; with the exception of the latter, clinical data are still scant for daily usage. Similarly happens with testosterone-derived anabolic drugs or with metabolism inhibitors such as hydrazine sulfate. With no doubt, progestogens, especially megestrol, and corticosteroids will be first-line therapies for anorexia-cachexia syndrome to stimulate the appetite and increase weight (megestrol), and have an effect on quality of life improvement and comfort in patients with advanced cancer.