LAUSR

BACKGROUND Current guidelines of the National Comprehensive Cancer Network and the European Society of Medical Oncology recommend regorafenib or trifluridine/tipiracil (TAS-102) for third-line therapy of metastatic colorectal cancer (mCRC). We evaluated the impact of regorafenib and TAS-102 treatment on skeletal muscle dynamics and sarcopenia. PATIENTS AND METHODS This retrospective analysis was based on unselected, consecutive mCRC patients treated with regorafenib and/or TAS-102 during third or later line of therapy at our tertiary-care cancer center in Salzburg, Austria. The skeletal muscle index (SMI, cm2/m2) and sarcopenia were evaluated from cross-sectional computed tomographic images at the level of the third lumbar vertebra. RESULTS Between January 2013 and April 2018, a total of 45 patients had received regorafenib and/or TAS-102. At initial mCRC diagnosis and at initiation of third-line therapy, 24% and 54% of patients presented with sarcopenia. A statistically significant skeletal muscle loss was observed during regorafenib treatment (median SMI change: -2.75 cm2/m2 [-6.3%]; P < .0001), which was not the case during TAS-102 therapy (-1.5 cm2/m2 [-3.5%]; P = .575). Furthermore, subclassification of patients into 3 groups-normal muscle mass, stable sarcopenia, and new-onset sarcopenia-at initiation of third-line therapy permitted discrimination of overall survival, with 1-year overall survival rates of 61%, 29%, and 16%, respectively (P = .04). CONCLUSION The frequency of sarcopenia increases during the course of mCRC and negatively affects survival. In contrast to TAS-102, regorafenib is associated with increased skeletal muscle loss during mCRC treatment and should therefore be used with caution in mCRC patients with preexisting sarcopenia or a history of recent weight loss.