Two faces of drug therapy in cancer: Drug-related lean tissue loss and its adverse consequences to survival and toxicity

Purpose of review: A common feature of cancer patients is loss of lean tissue, specifically skeletal muscle, which may be the result of the tumor or a side-effect of chemotherapy or other drugs. Lean tissue loss in turn has important adverse implications for toxicity of antineoplastic therapy and, hence, cancer prognosis. Recent findings: Contemporary cancer populations have heterogeneous proportions of lean tissue, regardless of body weight. Wasting of lean tissue during the cancer trajectory has been associated with tumor progression. Lean tissue depletion is an independent predictor of severe toxicity in patients treated with chemotherapeutic agents of diverse classes. Patients with lean tissue depletion behave as if overdosed and have toxicity of sufficient magnitude to require dose reductions, treatment delays or definitive termination of treatment. Muscle loss may occur due to a specific effect of a chemotherapy agent (i.e. sorafenib), androgen suppression therapy or other drugs (i.e. statins such as atorvastatin). Summary: Lean tissue wasting occurs due to cancer progression and may be exacerbated by several drug classes. This loss of lean tissue is not proportional to changes in body weight and is prognostic of enhanced treatment toxicity and reduced survival.