Baseline MR elastography tumor stiffness predicts survival in pancreatic ductal adenocarcinoma

Abstract Purpose To investigate whether a single baseline stiffness measurement by magnetic resonance elastography (MRE) predicts survival in pancreatic ductal adenocarcinoma (PDAC). Materials and Methods Consecutive participants with suspected PDAC were prospectively enrolled at a single center from January-2021 to July-2023 for conventional 3T-MRI and 3D-MRE. Subsequent treatment and followup were per standard of care. Resectability was determined through multidisciplinary review, including participants eligible for surgery after neoadjuvant therapy. Pancreatic stiffness maps were evaluated for the MRE ring sign, defined as high peripheral and lower central tumor stiffness. Participants were categorized by ring sign presence and homogeneous stiffness above or below median. Survival and disease progression were assessed using Kaplan-Meier analysis and Cox proportional hazards models. Results Eighty-one participants underwent pancreatic MRE, with PDAC histopathologically confirmed in 55 for analysis. 30 were resectable (6 after neoadjuvant chemotherapy), and 25 were non-resectable. Median tumor stiffness was 14.5 kPa (IQR 10.0-16.5 kPa, SD 5.1 kPa) overall, while 13.3 kPa (IQR 9.9-16.2 kPa, SD 4.7 kPa) in those without MRE ring sign. The presence of ring sign (hazard ratio, HR = 2.3 (95% CI 1.2-4.4); p<.05) and tumor stiffness >13.3 kPa (HR = 2.6 (1.4-5.1); p<.05) were independently associated with increased 3-year mortality. Kaplan-Meier estimates showed 3-year survival of 50% (95% CI 23-72%) in participants without ring sign and stiffness ≤13.3 kPa, 29% (95% CI 4-61%) for those without ring sign and stiffness >13.3 kPa, 8% (95% CI 1-22%) and 0% in non-resectable PDAC or with ring sign, respectively (log-rank across all four groups, p<.001). Similar stratification was observed for 3-year progression-free survival (p=.001). Conclusion Baseline MRE may predict disease progression and survival in newly diagnosed PDAC, with the MRE ring sign and high tumor stiffness identifying participants at highest risk. These findings support further evaluation of MRE as a potential biomarker for PDAC.