Cancer cachexia is a multifactorial syndrome defined by an ongoing loss of skeletal muscle mass (with or without loss of fat mass) that cannot be reversed by conventional nutritional support and leads to progressive functional impairment.
The pathophysiology is characterized by a negative protein and energy balance driven by a variable combination of reduced food intake and abnormal metabolism.
The metabolic conditions observed in cancer cachexia include:
• increased resting energy expenditure,
• loss of adipose tissue due to an increased lipolysis by tumor or host products, and
• loss of skeletal muscle resulting from a depression in protein synthesis combined with an increase in protein degradation.
Tumor factors, such as proteolysis-inducing factor, and host factors, such as pro-inflammatory cytokines, angiotensin II, and glucocorticoids, all contribute to the catabolic state of metabolism.
Cachexia has been described as an inflammatory reaction, mediated via cytokines and involving hypothalamic mechanisms, which interact with neurotransmitters that influence both appetite and metabolism.
Cancer cachexia represents a continuum with three stages of clinical relevance:
• refractory cachexia
Not all patients traverse the entire spectrum
Management must take into account the patient’s prognosis.
In early stages, the focus is on improving the functional capacity and prevention of further deterioration. Here, measures like nutritional supplementation and exercise therapy may be relevant.
Refractory cachexia represents a stage where reversal of weight loss seems no longer possible due to very advanced or rapidly progressive cancer unresponsive to anti-cancer therapy. In this stage, the burden and risks of artificial nutritional support likely outweigh any potential benefit. Therapeutic interventions focus typically on alleviating the consequences and complications of cachexia without increasing the patient’s distress.
• Nutritional counseling and education.
• Correct the correctables — such as nausea, vomiting, depression, and pain — that may contribute to reduced food intake.
• Drug therapy. Steroids and progestins have been found to be effective. Other drugs — such as thalidomide, cannabinoids, and nonsteroidal anti-inflammatory drugs — have been tried but not always proven beneficial.
Radbruch L, Elsner F, Trottenberg P, Strasser F, Fearon K: Clinical practice guidelines on cancer cachexia in advanced cancer patients. Aachen, Department of Palliative Medicine/ European Palliative Care Research Collaborative; 2010. Internet. Accessed on May 24, 2016.