Myosteatosis to predict postoperative morbidity in pancreatic ductal adenocarcinoma patients receiving neoadjuvant chemotherapy.

Abstract

e16754 Background: Myosteatosis (adipose deposits in muscle) can be detected on cross-sectional imaging through variations in Skeletal Muscle Density (SMD). Patients with myosteatosis tend to have lower overall survival, increased chemotherapy toxicity, and shorter progression-free intervals across cancer types. We investigated whether changes in myosteatosis during neoadjuvant chemotherapy can predict postoperative morbidity risk in patients with pancreatic ductal adenocarcinoma (PDAC). Methods: This is a retrospective cohort study from 2014-2019 of patients with biopsy-proven PDAC who completed neoadjuvant chemotherapy and R0/1 resection (R1: margin < 1mm or microscopically positive). We obtained preoperative patient (age at diagnosis, baseline body mass index (BMI), sex, race, comorbidities) and treatment data (neoadjuvant chemotherapy regimen and duration, time from completion of systemic therapy to surgery, type of operation). Primary outcomes were postoperative complications and 90-day readmission. Average SMD was measured using imaging analysis software at the L3 level on axial abdominal CT scans at the time of diagnosis and at completion of neoadjuvant therapy (SliceOmatic TomoVision QC, Can). We defined SMDΔ as the decrease in SMD during neoadjuvant chemotherapy. Descriptive statistics and Student’s t-test were performed with STATA. Results: We identified 44 patients who received neoadjuvant chemotherapy, achieved a R0/1 resection, and had available CT scans for body composition evaluation. The postoperative complication rate was 43% (n = 19) and 90-day readmission rate was 30% (n = 13). Lower SMD at diagnosis was associated with increased postoperative delirium (p < 0.01) and 90-day readmission (p = 0.02). Greater SMDΔ was associated with increased ICU utilization (p < 0.01) and tube feeding upon discharge (p = 0.03). There was no significant association between preoperative BMI or albumin and our primary outcomes. Conclusions: Preoperative SMD and SMDΔ, rather than albumin or BMI, can predict postoperative morbidity in PDAC patients who received neoadjuvant chemotherapy. This study provides the framework for future studies to develop and validate a tool to predict postoperative morbidity risk in these patients.