Therapeutic Efficacy of Tyrosine Kinase Inhibitors Treatment for Metastatic Renal Cell Carcinoma Using 18F-FDG PET/CT

Abstract
Background: Renal Cell Carcinoma (RCC) diagnosis increased due to increased use of cross-sectional imaging studies, metastases are common in RCC. 18F-FDG PET/CT has a limited role in detection of primary RCC, but it is helpful in restaging, detection of distant metastasis and can be used in assessment of number and sites of RCC metastasis as baseline for future re-treatments.
Nowadays therapy with drugs targeting vascular endothe-lial growth factor receptor such as Tyrosine Kinase Inhibitors (TKI) showed promising efficacy. Response to chemotherapy has been monitored by Response Evaluation Criteria in Solid Tumors (RECIST) based on size measurements.
Aim of Study: The aim of this study was to use FDG uptake as indicator for assessment of biological response of Renal Cell Carcinoma (RCC) metastatic deposits to Tyrosine Kinase Inhibitors (TKI).
Patients and Methods: 30 patients having pathologically proven metastatic RCC in post total nephrectomy state under-went PET/CT examination at private center in period between March 2017 and April 2018 and following a preset protocol as baseline study. They all received 4 cycles (six weeks cycles) of TKI therapy then all had a second PET/CT examination following same protocol after 6 months to assess therapeutic response.
Results: Out of 30 cases 22 cases (73.3%) showed disease regression, 6 cases (20%) showed stationary course and 2 cases (6.7%) showed disease progression.
Conclusion: 18F-FDG PET/CT is an effective index in monitoring efficacy of TKI treatment for RCC metastasis.