Cancer cachexia
Severe loss of weight and muscle in advanced cancer that eating more cannot reverse on its own. It affects up to eight in ten patients with advanced disease and contributes to a fifth of cancer deaths.
International consensus (Fearon 2011): weight loss over 5% in six months, or over 2% with BMI under 20 or sarcopenia, driven by tumour- and host-derived inflammatory mediators (IL-6, TNF, activin, GDF-15) that suppress appetite and increase muscle and fat catabolism. Staged as precachexia, cachexia and refractory cachexia. Distinct from starvation because it is inflammation-driven and only partly nutrition-responsive; treatment is multimodal (nutrition, exercise, anti-inflammatory or appetite drugs). GDF-15 blockade is the first mechanism-based therapy in phase 3.