Sarcopenia in cancer: Risking more than muscle loss

Abstract

Sarcopenia is characterised by progressive and extensive skeletal muscle degeneration and is associated with functional decline. Sarcopenia has primary and secondary aetiology, arising as a result of the ageing process or through chronic cytokine-mediated inflammation (associated with health conditions including cancer), respectively. Diagnosis of sarcopenia is dependent upon detection of reduced skeletal muscle strength, mass and performance. A combination of non-radiological and radiological methods can be used to assess each of these in turn to accurately diagnose sarcopenia. Sarcopenia is known to adversely affect outcomes of patients with various forms of cancer. Early identification of sarcopenia is imperative in improving patient care and overall prognosis. Various interventions, such as resistance exercise, nutritional support, and amino acid and vitamin supplementation have shown promise in the management of sarcopenia. However, further insight into novel interventions and indeed, assessment of the benefits of management of sarcopenia in terms of survival, are required to better support cancer patients.

Keywords: Biomarker; Cancer; Chemotherapy; Prognosis; Radiotherapy; Sarcopenia.

Fig. 1

Pathophysiology of primary and secondary sarcopenia.

Fig. 2

Segmentations of computed tomography scans at the level of the third lumbar vertebra (L3) in (A) a non-sarcopenic male patient and (B) a sarcopenic male patient. Blue segmentations indicate subcutaneous adipose tissue (sAT), purple segmentations indicate skeletal muscle (SM; paraspinal muscles adjacent to L3 and muscles of the abdominal wall); yellow segmentations indicate visceral adipose tissue [vAT] surrounding the abdominal viscera; and grey/blank segmentations indicate the abdominal organs (including the small and large bowel, liver and kidneys). Segmentation was processed using machine learning software . Clearly, there is little visible difference between some non-sarcopenic and sarcopenic patients, highlighting the importance of segmentation and calculation of SMI values. Abbreviations: SMI, skeletal muscle index.