Ligibel Jennifer A, Schmitz Kathryn H, Berger Nathan A
Division of Women's Cancers, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.
Department Public Health Sciences, Penn State College of Medicine, Hershey, PA, USA.
Transl Cancer Res. 2020 Sep;9(9):5760-5771. doi: 10.21037/tcr-2019-eaoc-05.
Sarcopenia, defined as loss of muscle mass, strength and physical performance, is a hallmark of aging and is invariably associated with perturbation of amino acid metabolism, increased muscle protein catabolism relative to anabolism, and loss of muscle fibers. Sarcopenia may be associated with general loss of body mass, or it may also occur along with obesity [sarcopenic obesity (SO)]. Although sarcopenia is associated with multiple comorbidities in older adults, its effects may even be more severe in patients with malignant disease where it has been shown to contribute to poor surgical outcomes, increased chemotherapy toxicity associated with both cytotoxic and targeted agents, as well as adversely impacting survival. While development of sarcopenia is a common age-related phenomenon, the associated catabolic processes appear to be promoted by physical inactivity, inadequate nutrition, and systemic low-grade inflammation, as well as intrinsic muscle and molecular changes, including mitochondrial dysfunction and impaired muscle stem cell regenerative capacity. Increased physical activity and adequate protein intake can reduce incidence and severity of sarcopenia in cancer patients, but many older cancer patients do not meet physical activity and nutrition recommendations, and cancer treatment can make it more difficult to make favorable lifestyle changes. Sarcopenia is discussed in terms of its adverse clinical consequences in older subjects and particularly, in older patients with cancer. Contributions of lifestyle, molecular, and cellular factors are likewise reviewed with suggestions for interventions to improve sarcopenia and its comorbid sequalae.
肌肉减少症被定义为肌肉质量、力量和身体机能的丧失，是衰老的一个标志，并且总是与氨基酸代谢紊乱、肌肉蛋白分解代谢相对于合成代谢增加以及肌肉纤维丧失相关。肌肉减少症可能与总体体重减轻有关，也可能与肥胖症（肌少症性肥胖，SO）同时发生。尽管肌肉减少症与老年人的多种合并症相关，但其影响在恶性疾病患者中可能更为严重，在这些患者中，肌肉减少症已被证明会导致手术效果不佳、与细胞毒性和靶向药物相关的化疗毒性增加，以及对生存率产生不利影响。虽然肌肉减少症的发生是一种常见的与年龄相关的现象，但相关的分解代谢过程似乎因身体活动不足、营养不足、全身性低度炎症以及内在的肌肉和分子变化（包括线粒体功能障碍和肌肉干细胞再生能力受损）而加剧。增加身体活动和充足的蛋白质摄入可以降低癌症患者肌肉减少症的发生率和严重程度，但许多老年癌症患者未达到身体活动和营养建议，并且癌症治疗会使做出有利的生活方式改变更加困难。本文将讨论肌肉减少症在老年受试者尤其是老年癌症患者中的不良临床后果。同样会回顾生活方式、分子和细胞因素的作用，并提出改善肌肉减少症及其合并症后遗症的干预建议。
