Skeletal muscle and visceral fat density are predictive imaging biomarkers for overall survival in patients with pancreatic adenocarcinoma: A retrospective multicenter analysis

RATIONALE AND OBJECTIVES: Utilizing a fully automated AI-generated body composition analysis (BCA) from PDAC staging computed tomography (CT) imaging to discover predictive imaging biomarkers for overall survival (OS). MATERIAL AND METHODS: Routine PDAC staging CTs (07/2012-12/2020) and clinicopathological data (Eastern Cooperative Oncology Group (ECOG) performance status, resection status, chemotherapy, age, CA19-9, Charlson Comorbidity Index, BMI) from four tertiary centers were collected retrospectively. Using a 3:1 split (training:holdout), we fitted Cox regression OS using every possible combination of 7 clinicopathological and 9 BCA variables: skeletal muscle index (SMI), area and density of total muscle compartment (TMC), skeletal muscle (SM), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and selected the combination with the lowest information complexity (ICOMP). The added value of BCA was calculated by comparing the BCA model with the base model (without BCA variables). RESULTS: Analysis included 472 PDAC patients (213 female, mean age 67.9 ± 11.5 years, resectable n = 170, unresectable n = 106, metastatic n = 196). Four clinicopathological (ECOG, resection status, chemotherapy, CA19-9) and 5 BCA variables (SMI, SM density, VAT density, TMC area, VAT area) were selected. Decreased SM density (myosteatosis) and increased VAT density showed strong association with OS (p = 0.0094 and 0.0019, respectively). The BCA model showed superior performance compared to the base model in all subgroups (AUC: resectable 0.76 versus 0.70, unresectable 0.76 versus 0.69, and metastatic 0.80 versus 0.75). CONCLUSION: BCA-identified myosteatosis and increased VAT density to be predictive imaging biomarkers for OS in all PDAC subgroups, potentially adding value to upfront risk stratification.