Body composition, defined as the proportions and distribution of lean and fat tissues in the human body, is an emergent theme in clinical oncology. Severe muscle depletion (sarcopenia) is most easily overlooked in obese patients; the advent of secondary analysis of oncologic images provides a precise and specific assessment of sarcopenia. Here, we review the definitions, prevalence and clinical implications of sarcopenic obesity (SO) in medical and surgical oncology. Reported prevalence of SO varies due to the heterogeneity in the definitions and the variability in the cut points used to define low muscle mass and high fat mass. Prevalence of SO in advanced solid tumor patient populations average 9% (range 2.3%-14.6%) overall, and one in four (24.7%, range 5.9%-39.2%) patients with body mass index ≥ 30 kg/m2 are sarcopenic. SO is independently associated with higher mortality and higher rate of complications in systemic and surgical cancer treatment, across multiple cancer sites and treatment plans. These associations remain unexplained, however, it has been hypothesized that patients with sarcopenia are generally unfit and unable to tolerate stress. Another proposed mechanism relates to increased exposure to antineoplastic therapy, i.e. a large fat mass would be expected to inflate drug dose in BSA-based treatments, causing an increased rate of dose-limiting toxicity. Pharmacokinetic data are needed to confirm or refute this hypothesis. Old age, deconditioning, cancer progression, acute or chronic nonmalignant disease and drug side-effects are suggested causes of muscle loss, and it is unknown the degree to which this can be reversed. Sarcopenia can be readily detected before start of cancer treatment, however, clinical management protocols for SO patients require development. Studies of cancer treatment dose-modulation are in progress.

中文翻译：

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少肌症肥胖症：隐藏的肌肉消瘦及其对癌症治疗的存活率和并发症的影响。

人体成分定义为人体中瘦肉和脂肪组织的比例和分布，是临床肿瘤学中的一个新兴主题。肥胖患者最容易忽视严重的肌肉耗竭（肌肉减少症）。肿瘤影像二次分析的出现为肌肉减少症提供了一种精确而具体的评估。在这里，我们审查医学和外科肿瘤学中的少肌症肥胖症（SO）的定义，患病率和临床意义。由于定义的异质性和用于定义低肌肉量和高脂肪量的切点的可变性，所报告的SO患病率有所不同。总的来说，晚期实体瘤患者中SO的患病率平均为9％（范围为2.3％-14.6％），而体重指数≥30 kg / m2的患者中，四分之一（24.7％，范围为5.9％-39.2％）为肌肉减少症。在多个癌症部位和治疗计划中，SO与全身性和手术性癌症治疗中更高的死亡率和更高的并发症发生率独立相关。这些关联仍然无法解释，但是，据推测，少肌症患者通常不适合并且不能耐受压力。另一个提出的机制涉及增加抗肿瘤治疗的暴露，即在基于BSA的治疗中，预期大量的脂肪会增加药物剂量，从而导致剂量限制毒性的发生率增加。需要药代动力学数据来确认或驳斥这一假设。衰老，衰弱，癌症进展，急性或慢性非恶性疾病以及药物副作用被认为是造成肌肉流失的原因，目前尚不清楚其可逆转的程度。在开始癌症治疗之前可以很容易地检测出肌肉减少症，但是，针对SO患者的临床治疗方案尚待开发。癌症治疗剂量调节的研究正在进行中。