Sarcopenia Is a Condition With Increasing Importance in Medical Oncology

Sarcopenia has increasingly been proposed as a predictor of response to treatment in oncology patients. In the August 2015 issue of The Oncologist, Arrieta et al. reported that routinely screening for sarcopenia and nutritional status was helpful in determining the next step of chemotherapy as well as toxicities in patientswithnon-smallcell lungcancer [1].Theauthorsspecifically addressed the association of sarcopenia with afatinib-related gastrointestinaltoxicityasanadverseeffect.However,theresults in this work seem to require somemore discussion. In the studybyArrieta etal. [1], sarcopeniawasassessedby computed tomography (L3 muscle index) based on the knowledge that it has high correlation with whole-body skeletal muscle mass. First, muscle mass estimation with computed tomography is a valuable optionbut it is not enough to identify sarcopenia correctly because the diagnosis of sarcopenia needs to be supported by clinical and laboratory measurements. Impairedmuscle function and strength,which have gained significant importance in recent years, are also importantcomponentsof sarcopenia accordingtoaconsensus report from the European Working Group on Sarcopenia in Older People [2, 3].The groupaddressed not onlymusclemass but also physical performance as assessed by gait speed, and grip strengthmeasured byhandheld dynamometer, to beused in an algorithmicworkup todecideon thepresenceor absence of sarcopenia. Second, the fixed wide ranges of attenuation values fordefiningmusclemassarea in thestudybyArrietaetal. remain relatively broad, which can lead to false distinction of tissues [4]. Moreover, the fixed wide ranges of attenuation make it harder to differentiate between presarcopenia and sarcopenia.Tosumup,althoughadecrease inmusclemasswas detected in 68.8% of the participants, it is not actually evident whatproportion thepatientshadtruesarcopenia.Clarification of these issues may be relevant to the study results.