Can CT texture analysis predict resectability and surgical outcomes after neoadjuvant radiotherapy in pancreatic cancer patients?

Purpose: To evaluate changes in texture analysis parameters of CT images after adjuvant stereotactic body radiation therapy (SBRT) in patients with locally advanced pancreatic adenocarcinoma. Material and methods: Pre- and post-SBRT contrast-enhanced CT examinations of 54 patients with locally advanced pancreatic adenocarcinoma were retrospectively evaluated. 3D regions of interest were manually drawn on arterial- and portal-phase CT images to comprise the whole tumor; 47 texture parameters were analyzed. Baseline and post-SBRT tumor volumes and texture parameters were compared between groups (resected versus non-resected and R0 versus R1-2 resection) using Wilcoxon test. Results: Forty patients (72.7%) underwent surgical resection after SBRT; among them, 25 had R0 resection (62.5%). Baseline tumor volume was not significantly different between groups (p>.05). Resected and R0 patients had significant tumor volume change after SBRT compared to non-resected and R1/2 patients (-39.7% vs +22.6%, p=.005; and -47.1% vs -17.3%, p=.017). Texture analysis identified 31 arterial-phase parameters and 27 portal-phase parameters significantly different before and after SBRT in resected tumors (p<.05). Among resected tumors, 22 arterial-phase parameters and 28 portal-phase parameters were significantly different after SBRT compared to baseline (p<.05). Conclusion: Texture analysis of contrast-enhanced CT images can identify changes after SBRT in locally advanced tumors that could be predictive of resectability and R0 resection.