The approval and use of molecular targeted agents for the first-line treatment of metastatic renal cell carcinoma (mRCC) has substantially improved the clinical outcome of patients. Although eventually all patients progress, hopes have been renewed with the approval of everolimus for patients who progress on or after treatment with tyrosine kinase inhibitors. In order to improve the prognosis for these patients, it is imperative to understand the reasons why patients with mRCC fail on first-line treatment. Currently, progression is assessed on the basis of the Response Evaluation Criteria in Solid Tumors, but it is known that targeted agents tend to cause disease stabilization rather than a significant decrease in tumor mass. Therefore, it may be time to evaluate the need to incorporate additional diagnostic methods in the assessment of disease response. Equally important is the study of the factors that determine the success or failure of second-line therapy in order to increase the chances of delivering the most effective and personalized therapy possible. In this article, we review the evidence related to the evaluation of patients with mRCC who fail on first-line treatment with targeted agents, including the systems to assess response and progression, the prognostic factors, the prognostic models that have been created based on these factors, and what is known about predictive biomarkers of disease outcome.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To investigate associations between computed tomographic (CT) features of clear cell renal cell carcinoma (RCC) and mutations in VHL, PBRM1, SETD2, KDM5C, or BAP1 genes.
Materials and methods:
The institutional review board approved this retrospective, hypothesis-generating study of 233 patients with clear cell RCC and waived the informed consent requirement. The study was HIPAA compliant. Three radiologists independently reviewed pretreatment CT images of all clear cell RCCs without knowledge of their genomic profile. One radiologist measured largest diameter and enhancement parameters of each clear cell RCC. Associations between CT features and mutations in VHL, PBRM1, SETD2, KDM5C, and BAP1 genes were tested by using the Fisher exact test. Associations between mutations and size and enhancement were assessed by using the independent t test. Interreader agreement was calculated by using the Fleiss κ.
Mutation frequencies among clear cell RCCs were as follows: VHL, 53.2% (124 of 233); PBRM1, 28.8% (67 of 233); SETD2, 7.3% (17 of 233); KDM5C, 6.9% (16 of 233); and BAP1, 6.0% (14 of 233). Mutations of VHL were significantly associated with well-defined tumor margins (P = .013), nodular tumor enhancement (P = .021), and gross appearance of intratumoral vascularity (P = .018). Mutations of KDM5C and BAP1 were significantly associated with evidence of renal vein invasion (P = .022 and .046, respectively). The genotype of solid clear cell RCC differed significantly from the genotype of multicystic clear cell RCC. While mutations of SETD2, KDM5C, and BAP1 were absent in multicystic clear cell RCC, mutations of VHL (P = .016) and PBRM1 (P = .017) were significantly more common among solid clear cell RCC. Interreader agreement for CT feature assessments ranged from substantial to excellent (κ = 0.791-0.912).
This preliminary radiogenomics analysis of clear cell RCC revealed associations between CT features and underlying mutations that warrant further investigation and validation.
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