title: Metastatic renal cell carcinoma imaging evaluation in the era of anti-angiogenic therapies.
abstract: During the last decade, the arsenal of anti-angiogenic (AAG) agents used to treat metastatic renal cell carcinoma (RCC) has grown and revolutionized the treatment of metastatic RCC, leading to improved overall survival compared to conventional chemotherapy and traditional immunotherapy agents. AAG agents include inhibitors of vascular endothelial growth factor receptor signaling pathways and mammalian target of rapamycin inhibitors. Both of these classes of targeted agents are considered cytostatic rather than cytotoxic, inducing tumor stabilization rather than marked tumor shrinkage. As a result, decreases in tumor size alone are often minimal and/or occur late in the course of successful AAG therapy, while tumor devascularization is a distinct feature of AAG therapy. In successful AAG therapy, tumor devascularization manifests on computed tomography images as a composite of a decrease in tumor size, a decrease in tumor attenuation, and the development of tumor necrosis. In this article, we review Response Evaluation Criteria in Solid Tumors (RECIST)-the current standard of care for tumor treatment response assessment which is based merely on changes in tumor length-and its assessment of metastatic RCC tumor response in the era of AAG therapies. We then review the features of an ideal tumor imaging biomarker for predicting metastatic RCC response to a particular AAG agent and serving as a longitudinal tumor response assessment tool. Finally, a discussion of the more recently proposed imaging response criteria and new imaging trends in metastatic RCC response assessment will be reviewed.
authors.affiliation: Department of Radiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
authors.forename: Reza
authors.initials: R
authors.lastname: Sirous
authors.affiliation: Department of Hematology/Oncology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Henegan
authors.affiliation: Center for Biostatistics and Bioinformatics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Radiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
authors.forename: Candace M
authors.initials: CM
authors.lastname: Howard
authors.affiliation: Department of Radiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
authors.forename: Frederico
authors.initials: F
authors.lastname: Souza
authors.affiliation: Department of Radiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA. asmith4@umc.edu.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Smith
mesh_terms: D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology*; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology*; D009362:Neoplasm Metastasis; D014057:Tomography, X-Ray Computed
chemical_list: D020533:Angiogenesis Inhibitors
keywords: Anti-angiogenic therapy; Imaging biomarker; Metastatic renal cell carcinoma; Tumor response