Sarcopenia in Metastatic Colorectal Carcinoma

Sarcopenia is the loss of skeletal muscle mass (SMM) and is associated with decreased muscle strength and/or decreased physical performance. Sarcopenia in patients with malignancies is a multifactorial problem, caused by chronic inflammation associated with malignancies, aging, nutritional deficiency, inactivity, and antineoplastic treatment. Sarcopenia is present in approximately 30-60% of patients with metastatic colorectal cancer (mCRC). It is an objective, measurable predictor of survival and systemic toxicity. The detection and quantification of sarcopenia in routine clinical practice does not require any particular test beyond routine imaging. Initial results show that regimens used to treat mCRC can have differential effect on skeletal mass. SMM tends to decrease during intensive regimens. Conversely, SMM tends to increase during low-intensity maintenance therapy or in patients with stable disease. The status of the underlying disease is another determinant of muscle mass changes, and SMM decreases during disease progression. Third-line therapy with regorafenib, a tyrosine kinase inhibitor of the vascular endothelial growth factor receptor, results in more skeletal muscle loss than trifluridine/tipiracil chemotherapy, which may have consequences for the survival or quality of life of patients. Larger prospective studies are needed to elucidate the importance of SMM changes during mCRC treatment. TB received fees for lectures and consultations related to the treatment of colorectal cancer from Merck, Amgen, Eli Lilly, Servier, Roche, Sanofi and Bayer. JH declares she has no potencional conflict of interest. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 15. 9. 2019 Accepted: 25. 10. 2019.