BACKGROUND Low skeletal muscle index (SMI) in metastatic colorectal cancer (mCRC) patients is associated with poor outcomes. The prognostic impact of SMI changes during consecutive palliative systemic treatments is unknown. METHODS This is a retrospective analysis of the phase 3 CAIRO3 study. The CAIRO3 study randomized 557 patients between maintenance capecitabine + bevacizumab (CAP-B) or observation, after six cycles capecitabine + oxaliplatin + bevacizumab (CAPOX-B). Upon first disease progression (PD1), CAPOX-B was reintroduced until second progression (PD2). SMI was assessed by computed tomography (CT) (total 1355 scans). SMI and body mass index (BMI) changes were analyzed for three time-periods; p1: during initial CAPOX-B, p2: randomization to PD1, and p3: PD1 to PD2. The association between absolute and change in SMI and BMI (both per 1 standard deviation) during p1-p3, with PD1, PD2, and survival was studied by Cox regression models. RESULTS This analysis included 450 of the 557 patients randomized in the CAIRO3 study. Mean SMI decreased during p1: mean -0.6 SMI units [95% CI -1.07;-0.26] and p3: -2.2 units [-2.7;-1.8], whereas during p2, SMI increased + 1.2 units [0.8-1.6]. BMI changes did not reflect changes in SMI. SMI loss during p2 and p3 was significantly associated with shorter survival (HR 1.19 [1.09-1.35]; 1.54 [1.31-1.79], respectively). Sarcopenia at PD1 was significantly associated with early PD2 (HR 1.40 [1.10-1.70]). BMI loss independent of SMI loss was only associated with shorter overall survival during p3 (HR 1.35 [1.14-1.63]). CONCLUSIONS In mCRC patients, SMI loss during palliative systemic treatment was related with early disease progression and reduced survival. BMI did not reflect changes in SMI and could not identify patients at risk of poor outcome during early treatment lines.

中文翻译：

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转移性结直肠癌患者的骨骼肌指数损失和生存率：3 期 CAIRO3 试验的二次分析。


背景转移性结直肠癌（mCRC）患者的低骨骼肌指数（SMI）与不良预后相关。连续姑息性全身治疗期间 SMI 变化对预后的影响尚不清楚。方法 这是对 3 期 CAIRO3 研究的回顾性分析。 CAIRO3 研究在六个周期卡培他滨 + 奥沙利铂 + 贝伐单抗 (CAPOX-B) 治疗后，将 557 名患者随机分为维持卡培他滨 + 贝伐单抗 (CAP-B) 或观察组。在第一次疾病进展 (PD1) 后，重新引入 CAPOX-B 直至第二次疾病进展 (PD2)。 SMI 通过计算机断层扫描 (CT) 进行评估（总共 1355 次扫描）。分析了三个时间段的 SMI 和体重指数 (BMI) 变化； p1：初始 CAPOX-B 期间，p2：随机分配至 PD1，p3：PD1 至 PD2。通过 Cox 回归模型研究了 p1-p3 期间 SMI 和 BMI（均为每 1 个标准差）的绝对值和变化与 PD1、PD2 和生存之间的关联。结果 这项分析包括 CAIRO3 研究中随机分配的 557 名患者中的 450 名。 p1 期间平均 SMI 下降：平均 -0.6 SMI 单位 [95% CI -1.07;-0.26] 和 p3：-2.2 单位 [-2.7;-1.8]，而 p2 期间，SMI 增加 + 1.2 单位 [0.8-1.6]。 BMI 的变化并不反映 SMI 的变化。 p2 和 p3 期间 SMI 丢失与较短的生存期显着相关（HR 分别为 1.19 [1.09-1.35]；1.54 [1.31-1.79]）。 PD1 时的肌肉减少症与早期 PD2 显着相关（HR 1.40 [1.10-1.70]）。独立于 SMI 损失的 BMI 损失仅与 p3 期间较短的总生存期相关（HR 1.35 [1.14-1.63]）。结论 在 mCRC 患者中，姑息性全身治疗期间 SMI 丧失与早期疾病进展和生存率降低有关。 BMI 不能反映 SMI 的变化，也不能识别早期治疗期间存在不良结果风险的患者。