Diffusion-weighted and multiphase contrast-enhanced MRI as surrogate markers of response to neoadjuvant sunitinib in metastatic renal cell carcinoma

Abstract

Background:Current imaging criteria for categorising disease response in metastatic renal cell carcinoma (mRCC) correlate poorly with overall survival (OS) in patients on anti-angiogenic therapies. We prospectively assess diffusion-weighted and multiphase contrast-enhanced (MCE) MR imaging (MRI) as markers of outcome.Methods:Treatment-naive mRCC patients on a phase II trial using sunitinib completed an MRI substudy. Whole-tumour apparent diffusion coefficient (ADC) maps and histograms were generated, and mean ADC and AUClow (proportion of the tumour with ADC values lying below the 25th percentile of the ADC histogram) recorded. On MCE-MRI, regions of interest were drawn around the most avidly enhancing components to analyse enhancement parameters. Baseline (n=26) and treatment-related changes in surviving patients (n=20) were correlated with OS. Imaged metastases were also analysed.Results:Forty-seven per cent of the patients showed significant changes in whole-tumour mean ADC following therapy, but there was no correlation with outcome. Patients with a high baseline AUClow and greater-than-median AUClow increase had reduced OS (HR=3.67 (95% confidence interval (CI)=1.23–10.9), P=0.012 and HR=3.72 (95% CI=0.98–14.21), P=0.038, respectively). There was no correlation between MCE-MRI parameters and OS. Twenty-eight metastases were analysed and showed positive correlation with primary tumour mean ADC for individual patients (r=0.607; P<0.001).Conclusion:Primary RCC ADC histogram analysis shows dynamic changes with sunitinib. Patients in whom the tumour ADC histogram demonstrated high baseline AUClow or a greater-than-median increase in AUClow with treatment had reduced OS.

Effect of Stereotactic Body Radiotherapy on the Growth Kinetics and Enhancement Pattern of Primary Renal Tumors

“…Several tumor imaging characteristics may be used to assess tumor response to treatment, including assessment of tumor vascularity with dynamic contrast-enhanced techniques such as ultrasound [31], CT [32], and MRI [33]; arterial spin labeling [34]; and measuring the apparent diffusion coefficient (ADC) on DWI [35]. Validation of these methods is ongoing.…”

Comparison of Utility of Histogram Apparent Diffusion Coefficient and R2* for Differentiation of Low-Grade From High-Grade Clear Cell Renal Cell Carcinoma

“…Compared with other histologic and clinical factors, including tumor size, microvascular invasion, necrosis, and invasion of the collecting system [8,9], high Fuhrman grade has been identified an independent risk factor for predicting metastasis after nephrectomy. Thus, preoperative characterization of the aggressiveness of clear cell RCC is vital for selecting the optimal therapy and thus helpful for improving active surveillance [10,11].DWI is gaining interest as a tool for determining localized renal mass, differentiating RCC subtypes, and predicting tumor aggressiveness [12][13][14][15][16][17]. Studies have shown differ-C lear cell renal cell carcinoma (RCC) is the most common type of primary renal malignancy in adults.…”

“…DWI is gaining interest as a tool for determining localized renal mass, differentiating RCC subtypes, and predicting tumor aggressiveness [12][13][14][15][16][17]. Studies have shown differ-C lear cell renal cell carcinoma (RCC) is the most common type of primary renal malignancy in adults.…”

Early Response Monitoring of Receptor Tyrosine Kinase Inhibitor Therapy in Metastatic Renal Cell Carcinoma Using [F-18]Fluorothymidine-Positron Emission Tomography-Magnetic Resonance

“…Both have been previously used for the assessment of treatment response in renal cell carcinoma. [10][11][12][13][14] After less than 3 weeks of therapy, we observed a more heterogeneous ADC map with an overall decline in ADC values within the metastatic lesions. There are several explanations for this observation: sunitinib-induced coagulative necrosis may occur following the decrease of blood flow.…”