Importance Sarcopenia and sarcopenic obesity have been associated with poor outcomes in unresectable pancreatic cancer (PC). Neoadjuvant treatment (NT) is used increasingly to improve resectability; however, its effects on fat and muscle body composition have not been characterized.

Objectives To evaluate whether NT affects muscle mass and adipose tissue in patients with borderline resectable PC (BRPC) and locally advanced PC (LAPC) and determine whether there were potential differences between patients who ultimately underwent resection and those who did not.

Design, Setting, and Participants In this retrospective cohort study conducted at 4 academic medical centers, 193 patients with BRPC and LAPC undergoing surgical exploration after NT who had available computed tomographic scans (both at diagnosis and preoperatively) and confirmed pancreatic ductal adenocarcinoma were evaluated. The study was conducted from January 2013 to December 2015. Data analysis was performed from September 2016 to May 2017. Measurement of body compartments was evaluated with volume assessment software before and after NT. A radiologist blinded to the patient outcome assessed the areas of skeletal muscle, total adipose tissue, and visceral adipose tissue through a standardized protocol.

Exposures Receipt of NT.

Main Outcomes and Measures Achievement of pancreatic resection at surgical exploration after the receipt of NT.

Results Of the 193 patients with complete radiologic imaging available after NT, 96 (49.7%) were women; mean (SD) age at diagnosis was 64 (11) years. Most patients received combined therapy with fluorouracil, irinotecan, oxaliplatin, leucovorin, and folic acid (124 [64.2%]) and 86 (44.6%) received chemoradiotherapy as well. The median interval between pre-NT and post-NT imaging was 6 months (interquartile range [IQR], 4-7 months). All body compartments significantly changed. The adipose compound decreased (median total adipose tissue area from 284.0 cm²; IQR, 171.0-414.0 to 250.0 cm²; IQR, 139.0-363.0; P < .001; median visceral adipose tissue area from 115.2 cm²; IQR, 59.9-191.0 to 97.7 cm²; IQR, 48.0-149.0 cm²; P < .001), whereas the lean mass slightly improved (median skeletal muscle from 122.1 cm²; IQR, 99.3-142.0 to 123 cm²; IQR 104.8-152.5 cm²; P = .001). Surgical resection was achievable in 136 (70.5%) patients. Patients who underwent resection had experienced a 5.9% skeletal muscle area increase during NT treatment, whereas those who did not undergo resection had a 1.7% decrease (P < .001).

Conclusions and Relevance Patients with PC experience a significant loss of adipose tissue during neoadjuvant chemotherapy, but no muscle wasting. An increase in muscle tissue during NT is associated with resectability.

重要的 骨肉减少症和肌肉减少症肥胖与不可切除的胰腺癌（PC）的不良预后相关。新辅助治疗（NT）越来越多地用于提高可切除性。然而，其对脂肪和肌肉体组成的影响尚未被表征。

目的 评估NT是否会影响边缘可切除PC（BRPC）和局部晚期PC（LAPC）患者的肌肉量和脂肪组织，并确定最终接受切除的患者与未接受切除的患者之间是否存在潜在差异。

设计，背景和参与者 在这项在4个学术医学中心进行的回顾性队列研究中，对193例NT术后接受了计算机X线断层扫描（诊断和术前检查）并确认了胰腺导管腺癌的BRPC和LAPC进行手术探查的患者进行了评估。该研究于2013年1月至2015年12月进行。数据分析于2016年9月至2017年5月进行。在NT之前和之后，使用体积评估软件对车厢的测量进行了评估。一位对患者结果不了解的放射科医生通过标准化协议评估了骨骼肌，总脂肪组织和内脏脂肪组织的面积。

新台币的曝光收据。

主要结果和措施 接受NT后在手术探查中切除胰腺的效果。

结果 193例在NT后可获得完整影像学检查的患者中，有96例（49.7％）为女性。诊断时的平均（SD）年龄为64（11）岁。大多数患者接受了氟尿嘧啶，伊立替康，奥沙利铂，亚叶酸和叶酸的联合治疗（124 [64.2％]）和86（44.6％）也接受放化疗。NT前和NT后影像之间的中位间隔为6个月（四分位间距[IQR]为4-7个月）。所有车厢都发生了明显变化。脂肪化合物减少（中位脂肪组织总面积中位数从284.0 cm ² ; IQR，171.0-414.0降至250.0 cm ² ; IQR，139.0-363.0; P  <.001;内脏脂肪组织中位数从115.2 cm ² ; IQR，59.9- 191.0至97.7 cm ²; IQR，48.0-149.0 cm ²；P  <.001），而瘦体重略有改善（中位骨骼肌从122.1 cm ² ; IQR为99.3-142.0至123 cm ² ; IQR 104.8-152.5 cm ² ; P  = .001）。136例（70.5％）患者可以手术切除。在NT治疗期间，接受切除的患者的骨骼肌面积增加了5.9％，而未接受切除的患者的骨骼肌面积减少了1.7％（P  <.001）。

结论与相关性 PC癌患者在新辅助化疗过程中会明显减少脂肪组织，但不会浪费肌肉。NT期间肌肉组织的增加与可切除性有关。