Cachexia is defined as an extreme wasting condition with marked weight loss, anorexia, and lassitude. About half of all cancer patients show a syndrome of cachexia characterized by loss of adipose tissue and skeletal muscle mass. Such patients have a decreased survival time compared with that of patients without weight loss. Abnormal metabolism is thought to be the basis of the cachexia status in advanced cancer patients. Cachexia induces the cytokines, in particular tumor necrosis factor (TNF)-α, IL-1, and IL-6, is thought to inhibit the activity of lipoprotein lipase (LPL), and thereby induces weight loss as a result of reduced fat accumulation in the tissues.

It is estimated that half of all patients with cancer eventually develop a syndrome of cachexia, with anorexia and a progressive loss of adipose tissue and skeletal muscle mass. Cancer cachexia is characterized by systemic inflammation, negative protein and energy balance, and an involuntary loss of lean body mass. It is an insidious syndrome that not only has a dramatic impact on patient quality of life, but also is associated with poor responses to chemotherapy and decreased survival. Cachexia is still largely an underestimated and untreated condition, despite the fact that multiple mechanisms are reported to be involved in its development, with a number of cytokines postulated to play a role in the etiology of the persistent catabolic state. Existing therapies for cachexia, including orexigenic appetite stimulants, focus on palliation of symptoms and reduction of the distress of patients and families rather than prolongation of life. Recent therapies for the cachectic syndrome involve a multidisciplinary approach. Combination therapy with diet modification and/or exercise has been added to novel pharmaceutical agents, such as Megestrol acetate, medroxyprogesterone, ghrelin, omega-3-fatty acid among others. These agents are reported to have improved survival rates as well as quality of life. In this review, we will discuss the emerging understanding of the mechanisms of cancer cachexia, the current treatment options including multidisciplinary combination therapies, as well an update on new and ongoing clinical trials.