骨骼肌质量低（肌减少）在癌症人群中很常见，并且与功能下降和死亡率相关，但之前的肿瘤学研究并未评估全身骨骼肌质量。相反，他们测量了替代指标，例如通过计算机断层扫描 (CT) 测量的 L3 骨骼肌横截面积 (CSA) 或通过双能 X 射线吸收测定法 (DXA) 测量的阑尾瘦肉质量 (ALM)。 D3-肌酸 (D3Cr) 稀释是一种评估全身骨骼肌质量的非侵入性方法，已在多种人群中进行了检查，但尚未在癌症中进行检查。为了比较 D3Cr 肌肉质量、CT CSA 和 DXA ALM 与肌减少和身体功能的关联，我们对 119 名结肠癌患者（2018-2022）进行了一项横断面研究。对于每种技术（D3Cr、CT 和 DXA） ，肌减少症被定义为其测量值的最低性别特异性四分位数。身体机能通过短时身体表现电池和握力来测量。我们计算了三种技术之间的 Pearson 相关性 (r)，计算了 Cohen 的 kappa 系数 (κ) 以评估肌细胞减少的一致性，并估计了三种技术与身体功能的 Pearson 相关性 (r)。所有分析均针对性别。61 名 (51.3%) 参与者为男性，平均（标准差）年龄为 56.6 (12.9) 岁，大多数 (68.9%) 具有较高的身体机能（短期身体机能电池：≥11）点）。三种技术之间的相关性和肌减少一致性在男性中高于女性；例如，关于 D3Cr 肌肉质量与 CT CSA 的比较，男性 r 为 0.73 (P < 0.001)，女性为 0.45 (P < 0.001)，κ 为 0.82 (95% CI: 0.65, 0.99)，男性为 0.24 (95女性 % CI：-0.08，0.52）。在男性中，较高的 D3Cr 肌肉质量与更快的步态速度（r = 0.43，P < 0.01）和更强的握力（r = 0.32，P < 0.05）显着相关； CT CSA 和 DXA ALM 也观察到类似的相关性。然而，在女性中，肌肉或瘦肉质量的测量结果与身体功能没有显着相关。这是第一项使用 D3-肌酸稀释方法来评估癌症人群肌肉质量的研究。不管用于肌肉或瘦体重评估的技术如何，我们观察到男性结肠癌患者比女性有更强的相关性、更大的肌减少一致性以及与身体功能更显着的关联。 D3Cr、CT 和 DXA 不能互换用于评估肌减少和身体功能，特别是对于患有结肠癌的女性。未来的研究应考虑这些技术的相对优势，并检查其他癌症类型中的 D3-肌酸稀释方法。© 2023 作者。 《恶病质、肌肉减少症和肌肉杂志》由 Wiley periodicals LLC 出版。

Low skeletal muscle mass (myopenia) is common in cancer populations and is associated with functional decline and mortality, but prior oncology studies did not assess total body skeletal muscle mass. Instead, they measured surrogates such as cross-sectional area (CSA) of skeletal muscle at L3 from computed tomography (CT) or appendicular lean mass (ALM) from dual-energy X-ray absorptiometry (DXA). D3-creatine (D3Cr) dilution is a non-invasive method to assess total body skeletal muscle mass, which has been examined in a variety of populations but not in cancer. To compare the associations of D3Cr muscle mass, CT CSA, and DXA ALM with myopenia and physical function, we conducted a cross-sectional study among 119 patients with colon cancer (2018-2022).For each technique (D3Cr, CT and DXA), myopenia was defined as the lowest sex-specific quartile of its measurement. Physical function was measured by the short physical performance battery and grip strength. We calculated Pearson correlations (r) among three techniques, computed Cohen's kappa coefficients (κ) to assess the agreement of myopenia, and estimated Pearson correlations (r) of three techniques with physical function. All analyses were sex-specific.Sixty-one (51.3%) participants were male, the mean (standard deviation) age was 56.6 (12.9) years, and most (68.9%) had high physical function (short physical performance battery: ≥11 points). Correlations and myopenia agreement among three techniques were greater in men than women; for example, regarding D3Cr muscle mass versus CT CSA, r was 0.73 (P < 0.001) for men versus 0.45 (P < 0.001) for women, and κ was 0.82 (95% CI: 0.65, 0.99) for men versus 0.24 (95% CI: -0.08, 0.52) for women. Among men, higher D3Cr muscle mass was significantly correlated with faster gait speed (r = 0.43, P < 0.01) and stronger grip strength (r = 0.32, P < 0.05); similar correlations were observed for CT CSA and DXA ALM. However, among women, no measure of muscle or lean mass was significantly associated with physical function.This is the first study using D3-creatine dilution method to assess muscle mass in a cancer population. Regardless of the techniques used for muscle or lean mass assessment, we observed stronger correlations, greater myopenia agreement, and more significant associations with physical function in men with colon cancer than women. D3Cr, CT and DXA are not interchangeable methods for assessing myopenia and physical function, especially in women with colon cancer. Future studies should consider relative advantages of these techniques and examine the D3-creatine dilution method in other cancer types.© 2023 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by Wiley Periodicals LLC.