Association Between Treatment-Emergent Pancreatic Volume Loss and Survival Outcomes in Patients with Metastatic Colorectal Cancer Receiving Bevacizumab.

Background and Objectives: The effect of bevacizumab on the morphology of non-tumoral organs remains unclear. We evaluated computed tomography (CT)- derived treatment-emergent pancreatic volume loss and examined its association with progression-free survival (PFS) and overall survival (OS) in patients with metastatic colorectal cancer receiving bevacizumab. Materials and Methods: This single-center retrospective study included 105 patients treated at Ankara Etlik City Hospital who had evaluable paired contrast-enhanced CT scans obtained before and during therapy. Pancreatic volume was measured on CT, and percentage volume loss was calculated. Clinical, laboratory, radiological, and survival data were retrospectively reviewed. Results: Mean pancreatic volume declined from 89.9 ± 6.1 mL before treatment to 83.6 ± 5.1 mL during therapy (p < 0.001). Albumin levels and platelet counts also decreased, whereas amylase, hemoglobin, and the neutrophil-to-lymphocyte ratio remained largely unchanged. In the main multivariable models, each 1% increase in pancreatic volume loss was associated with worse bevacizumab-line PFS (HR 1.06, 95% CI 1.02-1.10; p = 0.032) and OS (HR 1.08, 95% CI 1.01-1.15; p = 0.041). Percentage change in albumin was independently associated with both endpoints. Sensitivity analyses supported a more consistent association of pancreatic volume loss with PFS than with OS. Conclusions: Pancreatic volume decreased during bevacizumab-containing therapy. Greater pancreatic volume loss was associated with shorter PFS and OS; however, the association was more consistent for PFS. Prospective studies are needed to validate these findings and determine their clinical relevance.