Anorexia and Cachexia

Cachexia is a significant loss of muscle and adipose tissue occurring in patients with advanced cancer, chronic obstructive pulmonary disease, chronic infection including acquired immunodeficiency syndrome and tuberculosis, chronic heart failure, and rheumatoid arthritis. Increases in proinflammatory factors characterize cachexia. There is a decreased quality of life, decreased tolerance to surgical or medical interventions, and shortened survival.

The frequency and intensity of cachexia differ among cancers; patients with gastrointestinal, pancreatic, and lung cancers are more likely affected by cachexia than other tumors. By contrast, cachexia is relatively uncommon in patients with breast, sarcomas, and hematological malignancies. Cachexia is not simply starvation; fat stores replace glucose as the primary fuel. Cancer causes a change in metabolism instead of an energy deficit, so conventional nutritional support is insufficient.