Date of Award

1-1-2019

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Todd Schlachter

Second Advisor

Julius Chapiro

Abstract

The purpose of this study was to test and compare the ability of radiologic measurements of lesion diameter, volume, and enhancement on baseline magnetic resonance (MR) images to be predictors of overall survival (OS) and markers of treatment response in patients with liver-dominant colorectal cancer metastases undergoing loco-regional tumor therapies.

This retrospective study included 88 patients with colorectal cancer (CRC) liver metastases, treated with transarterial chemoembolization (TACE) or Y90 transarterial radioembolization (TARE) between 2001 and 2014. All patients received contrast-enhanced MRI prior to therapy. Semi-automated whole liver and tumor segmentations of three dominant lesions were performed on baseline MRI to calculate total tumor volume (TTV) and total liver volumes (TLV). Quantitative 3D analysis was performed to calculate enhancing tumor volume (ETV), enhancing tumor burden (ETB, calculated as ETV/TLV), enhancing liver volume (ELV), and enhancing liver burden (ELB, calculated as ELV/TLV). Overall and enhancing tumor diameters were also measured. Response assessment was analyzed in a subset of 63 patients who received 1-month MRI follow-up imaging using RECIST, mRECIST, change in ELV (deltaELV), vRECIST and qEASL. A modified Kaplan-Meier method was used to determine appropriate cutoff values to stratify patients based on these metrics. The predictive value of each parameter was assessed by Kaplan-Meier survival curves as well as univariate and multivariate cox proportional hazard models (statistical significance defined as p < .05).

In baseline imaging analysis, all methods except ELB achieved statistically significant separation of survival curves. Multivariate analysis showed a HR of 2.1 (95% CI 1.3-3.4, p=0.004) for enhancing tumor diameter, HR 1.7 (95% CI 1.1-2.8, p=0.04) for TTV, HR 2.3 (95% CI 1.4-3.9, p

In conclusion, tumor enhancement of CRC liver metastases on baseline MR imaging is strongly associated with patient survival after loco-regional tumor therapy, suggesting that ETV and ETB are better prognostic indicators than non-enhancement based and one-dimensional based markers. However, while volumetric-based methods are superior to 1D methods, enhancement-based methods of treatment response assessment were not successful in predicting survival. A potential implication of these findings as novel staging markers warrants prospective validation.

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