Cancer Treatment Centers of America (CTCA) at Midwestern Regional Medical Center, Zion, IL, United States of America.
PLoS One. 2019 Jun 20;14(6):e0218761. doi: 10.1371/journal.pone.0218761. eCollection 2019.
Sarcopenia, the presence of skeletal muscle mass depletion, can be objectively quantified, whereas subjective global assessment (SGA) is a widely utilized subjective instrument to assess nutritional status. Both the presence of sarcopenia and SGA-assessed malnutrition, in isolation, have been shown to be associated with worse overall survival in a wide range of cancers. However, there is no research evaluating the independent prognostic significance of both the presence of sarcopenia and malnutrition as part of the same analysis. We investigated the impact of sarcopenia on overall survival in colorectal cancer specifically controlling for malnutrition.
We examined a consecutive case series of 112 patients with colorectal cancer first seen at our institution between August 2012 and October 2017. Using computed tomography (CT) imaging, the cross-sectional area of muscles at the L3 vertebral level was measured and then divided by height squared to calculate skeletal muscle index (SMI). Sarcopenia was defined as SMI ≤38.5 cm2/m2 for women and ≤52.4 cm2/m2 for men. SGA assessments were completed within 2 weeks of CT imaging. The association of sarcopenia and malnutrition with overall survival was assessed using univariate and multivariate Cox regression analysis.
Median age at presentation was 53.3 years. Sixty-six (58.9%) patients had metastatic disease at diagnosis. Using SMI, 46 (41.1%) patients were sarcopenic, while 66 (58.9%) were non-sarcopenic. Using SGA, 69 (61.6%) patients were assessed as well-nourished, while 43 (38.4%) were malnourished. Of 69 patients classified as well-nourished by SGA, 22 (31.9%) were sarcopenic. Similarly, of 43 patients categorized as malnourished by SGA, 19 (44.2%) were non-sarcopenic. On multivariate analysis, after adjusting for age, gender, tumor stage, BMI, treatment history and SGA, patients with sarcopenia had 3 times greater risk of mortality compared to those without sarcopenia (p = 0.001). The median survival of patients with both sarcopenia and malnutrition (n = 24) was 14.6 months (95% CI: 10.5 to 18.6) compared to the median survival of 25.9 months (95% CI: 7.8 to 44.0) in patients who were either sarcopenic or malnourished but not both (n = 41; p = 0.001). The median survival of patients who were non-sarcopenic and well nourished (n = 48; p = 0.001) was 38.6 months (95% CI: 25.6 to 51.6).
The exploratory study suggests that presence of sarcopenia supersedes the presence of malnutrition as a predictor of survival in colorectal cancer. Co-existence of sarcopenia and malnutrition is associated with worse survival in colorectal cancer compared to just one of those conditions being present. Prospective studies with large sample sizes are needed to confirm these findings.
肌少症是骨骼肌质量减少的存在，可以通过客观的方法进行量化，而主观整体评估（SGA）是一种广泛用于评估营养状况的主观工具。肌少症的存在和 SGA 评估的营养不良均与多种癌症的总体生存率较差有关。然而，目前尚无研究评估肌少症和营养不良的存在作为同一分析的一部分的独立预后意义。我们研究了肌少症对结直肠癌总体生存率的影响，具体控制了营养不良的影响。
我们检查了 112 例在我们机构于 2012 年 8 月至 2017 年 10 月间首次就诊的结直肠癌连续病例系列。使用计算机断层扫描（CT）成像，测量 L3 椎体水平的肌肉横截面积，然后除以身高的平方以计算骨骼肌指数（SMI）。肌少症定义为女性 SMI≤38.5cm2/m2，男性 SMI≤52.4cm2/m2。在 CT 成像后 2 周内完成 SGA 评估。使用单变量和多变量 Cox 回归分析评估肌少症和营养不良与总体生存率的关联。
中位年龄为 53.3 岁。66 例（58.9%）患者在诊断时患有转移性疾病。使用 SMI，46 例（41.1%）患者为肌少症，66 例（58.9%）为非肌少症。使用 SGA，69 例（61.6%）患者被评估为营养良好，43 例（38.4%）为营养不良。在 SGA 被评估为营养良好的 69 例患者中，22 例（31.9%）为肌少症。同样，在 SGA 被评估为营养不良的 43 例患者中，19 例（44.2%）为非肌少症。多变量分析显示，在调整年龄、性别、肿瘤分期、BMI、治疗史和 SGA 后，与无肌少症患者相比，肌少症患者的死亡风险增加了 3 倍（p=0.001）。同时存在肌少症和营养不良的患者（n=24）的中位生存期为 14.6 个月（95%CI：10.5 至 18.6），而仅存在肌少症或营养不良但不同时存在两者的患者（n=41）的中位生存期为 25.9 个月（95%CI：7.8 至 44.0）（p=0.001）。非肌少症且营养良好的患者（n=48）的中位生存期为 38.6 个月（95%CI：25.6 至 51.6）（p=0.001）。
这项探索性研究表明，肌少症的存在比营养不良更能预测结直肠癌的生存率。肌少症和营养不良同时存在与结直肠癌的生存率较差有关，而不仅仅是其中一种情况存在。需要进行具有较大样本量的前瞻性研究来证实这些发现。
