研究术前身体成分分析对中低位直肠癌（RC）患者肌肉和脂肪组织分布与长期肿瘤学预后的作用，这些患者接受了治愈意图手术。最终分析纳入了155例于2014年1月至2016年12月之间接受治愈意图手术的中低位直肠癌患者。使用术前CT影像回顾性测量骨骼肌面积（SMA）、骨骼肌放射密度（SMD）、内脏脂肪面积（VFA）和脂肪多裂间隙面积（MFA）。为了根据患者身高标准化面积，将SMA除以身高的平方（m2）并获得肌肉质量指数（SMI，cm2/m2）。男女分别取分布的中位数作为SMI、SMD、VFA和MFA的分界点。进行单变量和多变量分析，评估身体组成与长期肿瘤学预后之间的关联。总生存期（OS）以月为单位，从原发手术日起至任何原因死亡。无病生存期（DFS）定义为手术和肿瘤复发之间的间隔。使用Kaplan-Meier方法和log-rank检验验证预后生物标志物。使用ICC评估SMA、SMD、MFA和VFA的观察者间和观察者内的重现性。在随访期间，42名（27.1％）患者出现了肿瘤复发；21名（13.5％）患者死亡。SMI的性别特异性中位数值为女性28.6 cm2/m2，男性48.2 cm2/m2。SMD的性别特异性中位数值为女性34.7 HU，男性37.4 HU。VFA的性别特异性中位数值为女性123.1 cm2，男性123.2 cm2。MFA的性别特异性中位数值为女性13.8 cm2，男性16.0 cm2。在Cox回归多变量分析中，SMI（P=0.036）、SMD（P=0.022）和术后并发症等级（P=0.042）在死亡组和非死亡组之间有显着差异；SMD（P=0.011）和MFA（P=0.022）在复发组和非复发组之间有显着差异。VFA没有显示任何显着差异。使用Kaplan-Meier方法和log-rank检验，在高MFA患者中DFS显着较长（P=0.028），在低SMD患者中DFS显着较短（P=0.010），在低SMI患者中OS显着较短（P=0.034）并且低SMD的患者OS也显着较短（P=0.029）。定量评估初步诊断时骨骼肌质量和脂肪组织分布是RC患者长期肿瘤学预后的重要预测因素。SMD和SMI是预测接受根治手术的中低位直肠癌患者OS的独立因素。SMD和MFA是预测接受根治手术的中低位直肠癌患者DFS的独立因素。 © 2023年作者。

To investigate the role of preoperative body composition analysis for muscle and adipose tissue distribution on long-term oncological outcomes in patients with middle and low rectal cancer (RC) who received curative intent surgery.A total of 155 patients with middle and low rectal cancer who underwent curative intent surgery between January 2014 and December 2016 were included for the final analysis. Skeletal muscle area (SMA), skeletal muscle radiodensity (SMD), visceral fat area (VFA) and mesorectal fat area (MFA) were retrospectively measured using preoperative CT images. To standardize the area according to patient stature, SMA was divided by the square of the height (m2) and the skeletal muscle mass index (SMI, cm2/m2) was obtained. Each median values of the distribution in male and female served as cut-off point for SMI, SMD, VFA, and MFA, respectively. Univariate and multivariate analysis were performed to evaluate the association between body composition and long-term oncological outcomes. Overall survival (OS) measured in months from the day of primary surgery until death for any cause. Disease-free survival (DFS) was defined as the interval between surgery and tumor recurrence. The Kaplan-Meier method with log-rank testing was used to validate prognostic biomarkers. Intraclass correlation coefficient (ICC) was used to evaluate interobserver and intraobserver reproducibility for SMA, SMD, MFA,VFA.During the follow-up period, 42 (27.1%) patients had tumor recurrence; 21 (13.5%) patients died. The sex-specific median value of SMI was 28.6 cm2/m2 for females and 48.2 cm2/m2 for males. The sex-specific median value of SMD was 34.7 HU for females and 37.4 HU for males. The sex-specific median value of VFA was 123.1 cm2 for females and 123.2 cm2 for males. The sex-specific median value of MFA was 13.8 cm2 for females and 16.0 cm2 for males. In the Cox regression multivariate analysis, SMI (P = 0.036), SMD (P = 0.022), and postoperative complications grades (P = 0.042) were significantly different between death group and non-death group; SMD (P = 0.011) and MFA (P = 0.022) were significantly different between recurrence group and non-recurrence group. VFA did not show any significant differences. By the Kaplan-Meier method with log-rank testing, DFS was significantly longer in patients with high-MFA (P = 0.028) and shorter in patients with low-SMD (P = 0.010), OS was significantly shorter in patients with low-SMI (P = 0.034) and low-SMD (P = 0.029).Quantitative evaluation of skeletal muscle mass and adipose tissue distributions at initial diagnosis were important predictors for long-term oncologic outcomes in RC patients. SMD and SMI were independent factors for predicting OS in patients with middle and low rectal cancer who had radical surgery. SMD and MFA were independent factors for predicting DFS in patients with middle and low rectal cancer who had radical surgery.© 2023. The Author(s).