Metastatic Renal Cell Carcinoma: Radiologic Findings and Assessment of Response to Targeted Antiangiogenic Therapy by Using Multidetector CT

Abstract

Recent advances in treatment of metastatic renal cell carcinoma (RCC), such as new molecular therapies that use novel antiangiogenic agents, have led to revision of the most frequently used guideline to evaluate tumor response to therapy: Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Assessment of the response of metastatic RCC to therapy has traditionally been based on changes in target lesion size. However, the mechanism of action of newer antiangiogenic therapies is more cytostatic than cytotoxic, which leads to disease stabilization rather than to tumor regression. This change in tumor response makes RECIST 1.1--a system whose criteria are based exclusively on tumor size--inadequate to discriminate patients with early tumor progression from those with more progression-free disease and prolonged survival. New criteria such as changes in attenuation, morphology, and structure, as seen at contrast-enhanced multidetector computed tomography (CT), are being incorporated into new classifications used to assess response of metastatic RCC to antiangiogenic therapies. The new classifications provide better assessments of tumor response to the new therapies, but they have some limitations. The authors provide a practical review of these systems--the Choi, modified Choi, and Morphology, Attenuation, Size, and Structure (MASS) criteria--by explaining their differences and limitations that may influence the feasibility and reproducibility of these classifications. The authors review the use of multidetector CT in the detection of metastatic RCC and the different appearances and locations of these lesions. They also provide an overview of the new antiangiogenic therapies and their mechanisms of action and a brief introduction to functional imaging techniques. Functional imaging techniques, especially dynamic contrast-enhanced CT, seem promising for assessing response of metastatic RCC to treatment. Nonetheless, further studies are needed before functional imaging can be used in routine clinical practice.

Gastrointestinal Involvement of Recurrent Renal Cell Carcinoma: CT Findings and Clinicopathologic Features

“…RCC primarily metastasizes either by hematogenous or lymphatic dissemination (24). The tumor cells can spread into the inferior vena cava, which extends into the right chamber of the heart (25), or can invade regional lymph nodes and traverse the thoracic duct.…”

Seeding Metastasis of Chromophobe Renal Cell Carcinoma after Robot-Assisted Laparoscopic Partial Nephrectomy

“…The chromophobe subtype has a better prognosis than clear cell RCC. RCC usually metastasizes to the lung, bone, lymph node, liver, adrenal gland, and brain through hematogenous and lymphatic pathways (5). Seeding metastases of RCC are rare, with a previous study reporting merely 1% incidence of seeding metastasis of RCC (25 cases of metastasis of 2561 patients with RCC); there has been only one reported case of chromophobe RCC with seeding metastasis (3).…”

Three-dimensional Dynamic Contrast-enhanced US Imaging for Early Antiangiogenic Treatment Assessment in a Mouse Colon Cancer Model

“…Therefore, there is a critical need to develop noninvasive functional or molecular imaging methods to assess response to therapy and for earlier identification of responders from nonresponders. Dynamic contrast material-enhanced (DCE) computed tomographic (CT) and magnetic resonance (MR) imaging were shown to depict therapyinduced changes in tumor perfusion before there were changes in lesion size (8)(9)(10)(11). While promising, DCE CT imaging is associated with ionizing radiation, and the use of contrast media with MR or CT imaging is limited in patients with renal insufficiency.…”