Neuroendocrine Liver Metastasis Treated by Using Intraarterial Therapy: Volumetric Functional Imaging Biomarkers of Early Tumor Response and Survival

Abstract

Purpose To determine if volumetric changes of diffusion-weighted and contrast material–enhanced magnetic resonance (MR) imaging can help assess early tumor response to intraarterial therapy (IAT) in neuroendocrine liver metastasis (NELM). Materials and Methods This retrospective single-center comprehensive imaging analysis was performed in compliance with HIPAA and was institutional review board approved. Informed patient consent was waived. Seventy-one patients (39 men; mean age, 62.3 years) with NELM treated with IAT were analyzed retrospectively. MR studies were performed before and 3–4 weeks after therapy. The index lesion was segmented to provide volumetric functional analysis of apparent diffusion coefficient (ADC) and contrast-enhanced MR imaging in the hepatic arterial phase (HAP) and portal venous phase (PVP). Tumor response was defined as increase in volumetric ADC of 15% or greater and decrease in volumetric enhancement of 25% or greater during the HAP or of 50% or greater during the PVP. Patient overall survival was the primary end point after therapy initiation. Univariate analysis included Kaplan-Meier survival curves. The Cox proportional hazards regression model was used to detect interactions between volumetric ADC and contrast-enhanced MR imaging and to calculate the hazard ratio. Results There was significant increase in mean volumetric ADC (27%, P < .0001) and significant decrease in mean volumetric enhancement during the HAP (−25.3%, P < .0001) and the PVP (−22.4%, P < .0001) in all patients. Patients who had 15% or greater volumetric ADC increase (n = 49) after therapy had better prognosis than those who had less than 15% increase in volumetric ADC (n = 22) (log-rank test, P < .002). Patients who had 25% or greater decrease in volumetric arterial enhancement (n = 40) or 50% or greater decrease in venous enhancement (n = 18) had better prognosis than those who had less than 25% decrease in volumetric arterial enhancement (n = 31) or less than 50% decrease in venous enhancement (n = 53) (log-rank test, P < .02). Conclusion Volumetric functional MR imaging criteria may act as biomarkers of early response, indicating that these criteria may be important to incorporate in future NELM clinical trials.

Can volumetric ADC measurement help predict response to Y90 radioembolization in HCC?

“…Results from their studies suggest that ADC is an earlier surrogate of response compared to size criteria [6]. A survival benefit was demonstrated in cholangiocarcinoma treated by TACE and in neuroendocrine liver metastases treated by intraarterial therapy exhibiting response by ADC [10,11]. One of their study focused on the identification of volumetric functional response criteria of unresectable HCC treated by intraarterial therapy and confirmed that 3D ADC parameters permit to stratify survival [16].…”

“…In addition, volumetric delineation may replace uni/bidimensional measurements as imaging software and spatial resolution of imaging modalities evolve [2,8,9]. Beyond conventional mean apparent diffusion coefficient (ADC), volumetric ADC measurement provides more realistic tumor delineation compared to uni-or bi-dimensional approaches, and permits analyzing tumor response heterogeneity by generating histograms from voxel-by-voxel ADC values calculation [10][11][12]. The aim of the present study was to correlate changes in different anatomical (RECIST, anatomical volume), enhancement (mRE-CIST), and DWI parameters with post-transplant pathological analysis, and to discuss the added value of mRECIST and volumetric DWI combination for the response assessment of HCC after 90 Yttrium radioembolization (Y90).…”

Volumetric assessment of tumour response using functional MR imaging in patients with hepatocellular carcinoma treated with a combination of doxorubicin-eluting beads and sorafenib

“…However, volumetric enhancement was unable to provide similar results, likely because cholangiocarcinoma is a relatively hypovascular tumour [16]. Finally, in patients with hepatocellular carcinoma and neuroendocrine tumour liver metastasis, both volumetric ADC and enhancement proved adequate in differentiating responders from non-responders, with a significant survival benefit for the responders [17, 18, 25]. …”

GEP-NETS UPDATE: Interventional radiology: role in the treatment of liver metastases from GEP-NETs

“…Lipiodol uptake is a biomarker of response with CT; however, its strong radio-opacity may render difficult the evaluation of small foci of enhancement. MRI is the most sensitive cross-sectional imaging technique for depiction of endocrine tumor liver metastases (14,15) and can predict early tumor response to TACE with the help of volumetric imaging, where a 25% or greater decrease in arterial enhancement or 50% or greater decrease in venous enhancement correlate with better prognosis (16). The best imaging technique to monitor response after RE is still debated, with morphological response occurring often several months later than with other techniques (17,18).…”