Identifying enhancement-based staging markers on baseline MRI in patients with colorectal cancer liver metastases undergoing intra-arterial tumor therapy

Abstract

Objectives: To determine if three-dimensional whole liver and baseline tumor enhancement features on MRI can serve as staging biomarkers and help predict survival of patients with colorectal cancer liver metastases (CRCLM) more accurately than one-dimensional and non-enhancement-based features.

Methods: This retrospective study included 88 patients with CRCLM, treated with transarterial chemoembolization or Y90 transarterial radioembolization between 2001 and 2014. Semi-automated segmentations of up to three dominant lesions were performed on pre-treatment 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. A modified Kaplan-Meier method was used to determine appropriate cutoff values for each metric. The predictive value of each parameter was assessed by Kaplan-Meier survival curves and univariable and multivariable cox proportional hazard models.

Results: All methods except whole liver (ELB, ELV) and one-dimensional/non-enhancement-based methods were independent predictors of survival. Multivariable 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 < 0.001) for ETV, and HR 2.4 (95% CI 1.4-4.0, p = 0.001) for ETB.

Conclusions: Tumor enhancement of CRCLM on baseline MRI is strongly associated with patient survival after intra-arterial therapy, suggesting that enhancing tumor volume and enhancing tumor burden are better prognostic indicators than non-enhancement-based and one-dimensional-based markers.

Key points: • Tumor enhancement of colorectal cancer liver metastases on MRI prior to treatment with intra-arterial therapies is strongly associated with patient survival. • Three-dimensional, enhancement-based imaging biomarkers such as enhancing tumor volume and enhancing tumor burden may serve as the basis of a novel prognostic staging system for patients with liver-dominant colorectal cancer metastases.

Keywords: Colorectal neoplasms; Magnetic resonance imaging; Neoplasm staging; Radiology, interventional; Treatment outcome.

Fig. 1

Flow chart of study population

Fig. 2

MRI assessment techniques. a Measurements of one-dimensional overall diameter. b One-dimensional measurement of enhancing tumor diameter. c Red outline shows liver segmentation which gives total liver volume (TLV). Subsequent qEASL analysis gives enhancing liver volume (ELV). ELV/TLV gives enhancing liver burden (ELB). d Red outline shows tumor segmentation which gives total tumor volume (TTV). Subsequent qEASL analysis gives enhancing tumor volume (ETV). ETV/TLV gives enhancing tumor burden (ETB). Of note, these images are prior to subtraction which is performed before qEASL analysis

Fig. 3

Kaplan-Meier survival curves plotted for each image assessment technique. ELB was the only parameter that did not demonstrate significant separation of curves