Interstitial Brachytherapy of the Liver for Renal Cell Carcinoma: ADC Measurements Do Not Predict Overall Survival.

Abstract

To assess the influence of pre-treatment apparent diffusion coefficient (ADC) measurements on outcomes in patients undergoing interstitial brachytherapy (iBT) for liver metastases from renal cell carcinoma. Patients undergoing iBT for renal cell carcinoma (RCC) liver metastases were retrospectively identified. Patients were eligible for inclusion if they had a pre-treatment magnetic resonance imaging (MRI) with diffusion weighted imaging (DWI) sequences. For each lesion, a region of interest (ROI) was placed along the contours of the entire lesion across all slices. For each ROI, ADC minimum, mean and maximum as well as the lesion area were noted, and the average was calculated for each lesion. ADC measurements were correlated with overall survival. The analysis included 17 patients. Median overall survival was 36 months. Neither ADC measurement was significantly associated with overall survival. ADC min (HR=1.00, 95%CI=1.00-1.00, p=0.600), ADC max (HR=1.001, 95%CI=0.998-1.003, p=0.490), ADC mean (HR=0.999, 95%CI=0.996-1.003, p=0.638). ADC is not able to differentiate between groups with good and bad overall survival in patients undergoing iBT for RCC liver metastases.