ASCO GU 2017: Best of journals: Renal Cell Carcinoma - Radiologist - Session Highlights

Orlando, Florida USA ( Several important and innovative papers that were published in 2016, were reviewed.

First, a prospective evaluation of Tc-sestamibi SPECT/CT for diagnosis of renal oncocytoma was examined. Pilot studies suggest that Tc-Sestamibi SPECT/CT can be used to differentiate oncocytomas from RCC's. Nuclear imaging offers a potential non invasive means of determining the histology of renal tumors and may reduce unnecessary biopsies or surgeries in patients with an indeterminate renal mass. The objective of the study was to evaluate the accuracy of SPECT/CT for differentiation of oncocytoma and other histologies. The study showed that oncocytoma had higher intake compared to other pathologies. The inter observer agreement was high. The limitations of this study were small sample size, single institute and only 2 readers. The conclusion was that SPECT/CT is a promising imaging test for differentiating oncocytoma from other renal histologies.

Second, a radiogenomic risk score was examined as a stratification tool for outcomes in a renal cell cancer phase 2 clinical trial. A radiogenomic risk score (RRS) incorporating 4 CT imaging features may be predictive of metastatic RCC response to anti angiogeneic therapy. The features include % necrosis, sharpness of interface between tumor and normal tissue, rim of enhancement and hypo attenuating rim at the edge. The objective of the trial was to evaluate the potential of the RRS for stratifying PFS in patients with mRCC undergoing pre-surgical treatment with bevacizumab.this was a prospective single institute phase 2 observational trial. Patient with mRCC treated with neoadjuvant bevacizumab were included. The outcomes were time to progression (TTP) and OS. The Kaplan Meier analyses showed improved TTP and OS for patients with low risk RRS compared to high risk. MVA revealed a HR of 8.58 for RRS. The limitation of this study are small sample size, single institution and only 2 readers. The authors conclude that RRS stratifies PFS in patients with mRCC undergoing pre-surgical bevacizumab and cytoreductive nephrectomy.

Lastly, early tumor shrinkage was evaluated as a tool for detection of early clinical activity in mRCC. Tumor size changes are relatively small in patients with mRCC treated with targeted therapy. However, early tumor shrinkage (eTS) is predictive and prognostic in multiple studies. The objective of this trial was to evaluate the degree of eTS following systemic therapy and may predict survival in mRCC. This was a retrospective post-hoc analysis of pooled data from phase 2 and 3 studies conducted between 2003 and 2013. Patients from phase 2 and 3 sponsored by Pfizer who received sunitinib, axitinic, sorafenib, INF alpha, bevacizumab and temsirulimus were included.eTS was defined as >10% decrease in tumor size on the initial post therapy CT. Outcomes were PFS and OS. HR for PFS and OS according to eTS status were 1.59 and 1.63, both statistically significant. The limitations of this study were variability in timing of initial post therapy CT study, no inter observer assessment and unclear if size is predictive or prognostic. The conclusion was that eTS at first post baseline assessment is predictive and prognostic for a number of different therapies for mRCC

Presenter: Andrew Smith, MD, PhD, University of Mississippi Medical Center

Written By: Miki Haifler, MD, M.Sc, Fox Chase Cancer Center

at the 2017 Genitourinary Cancers Symposium - February 16 - 18, 2017 – Orlando, Florida USA