Extracellular volume fraction can predict the treatment response and survival outcome of colorectal cancer liver metastases.

ABSTRACT

OBJECTIVE: To assess the prognostic value of pre- and post-therapeutic changes in extracellular volume (ECV) fraction of liver metastases (LMs) for treatment response (TR) and survival outcomes in colorectal cancer liver metastases (CRLM). METHODS: 186 LMs were confirmed by pathology or follow-up (Training 130; Test 56). We analyzed the changes in ECV fraction of LMs before and after 2 cycles of chemotherapy combined with bevacizumab. After 12 cycles, we evaluated the TR on LMs based on the RECIST v1.1. Relative changes in ECV fraction and Hounsfield Units (HU), defined as ΔECV and ΔHU, were associated with progression-free survival (PFS), overall survival (OS), and TR. We identified TR predictors with multivariate logistic regression and PFS, OS risk factors with COX analysis. RESULTS: 186 LMs were classified as TR lesions (TR+ 84) and non-TR lesions (TR-102). ΔECV, ΔHUA-E, and texture could distinguish the TR of LMs in training and test set (P < 0.05). ΔECV [Odds ratio (OR) 1.03; 95% Confidence interval (CI) 1.02-1.05, P < 0.01] was an independent predictor of TR-. Area under the curve (AUC), sensitivity and specificity of TR model in training and test set were 0.87, 0.84, 90.14%, 90.32%, 72.88%, 64.00%, respectively. High CRD_score indicates that patients have shorter PFS [Hazard ratio (HR) 2.01; 95%CI 1.02-3.98, P = 0.045)] and OS (HR 1.89, 95%CI 1.04-3.42, P = 0.038). CONCLUSION: ΔECV can be used as an independent predictor of TR of CRLM chemotherapy combined with bevacizumab.