ASO Visual Abstract: Change Impact of Body Composition during Neoadjuvant Chemoradiotherapy in Patients with Resectable and Borderline Resectable Pancreatic Ductal Adenocarcinoma Undergoing Pancreatectomy

Background: The change impact of body composition during neoadjuvant therapy on clinical outcomes in patients with pancreatic ductal adenocarcinoma (PDAC) remains unclear. The aim of this study was to investigate the association between changes in body composition during neoadjuvant chemoradiotherapy (NACRT) and postoperative outcomes in patients with PDAC undergoing pancreatectomy, using three-dimensional images. Methods: We reviewed 66 consecutive patients with resectable/borderline resectable PDAC receiving gemcitabine and S-1 with radiotherapy between April 2010 and June 2016. Body compositions were evaluated pre- and post-NACRT. All patients were hospitalized and supplied with regulated diet during NACRT treatment. Results: Psoas major muscle volume index (PMI), abdominal fat volume index, and visceral fat volume index decreased significantly after NACRT (P < 0.0001, P < 0.0001, P < 0.0001, respectively). The post-NACRT CA19-9 level decreased significantly in the small-PMI-decrease group compared with the large-PMI-decrease group (P = 0.046). Recurrence-free survival (RFS) and overall survival (OS) of the large-PMI-decrease group were significantly poorer than those of the small-PMI-decrease group (P = 0.002, P = 0.006, respectively). On the other hand, there were no significant differences in RFS and OS between groups with high and low PMI, at the point of either pre-NACRT (P = 0.117, P = 0.123, respectively) or post-NACRT (P = 0.065, P = 0.064, respectively). Multivariate analysis identified a large percentage decrease in PMI as an independent risk factor for recurrence and death (P = 0.003, P = 0.002, respectively). Conclusions: Loss of skeletal muscle mass during NACRT was an independent risk factor for survival in patients with PDAC. © 2022, Society of Surgical Oncology.