Optimal use of imaging to guide treatment decisions for kidney cancer

Area of Science:

• Oncology
• Radiology
• Medical Imaging

Background:

• Treatment monitoring for solid tumors, particularly metastatic renal cancer, traditionally relies on cross-sectional imaging to assess tumor burden.
• Targeted therapies, including mammalian target of rapamycin (mTOR) and vascular endothelial growth factor (VEGF) pathway inhibitors, present challenges for standard imaging metrics.
• Existing RECIST (Response Evaluation Criteria in Solid Tumors) criteria may not accurately reflect treatment response or progression with these agents.

Purpose of the Study:

• To evaluate the limitations of current imaging-based treatment monitoring for metastatic renal cancer.
• To explore alternative imaging approaches and their clinical utility.
• To determine the most pragmatic approach for treatment decision-making in the absence of mature predictive biomarkers.

Main Methods:

• Review of current practices in solid tumor and metastatic renal cancer treatment monitoring.
• Analysis of proposed alternative imaging metrics, including relative RECIST, volumetric measurements, and functional imaging (e.g., DCE-MRI, FDG-PET).
• Assessment of available data supporting the clinical use of these alternative methods and baseline imaging characteristics for therapy selection.

Main Results:

• Standard RECIST metrics are inadequate for capturing the effects of mTOR and VEGF pathway-directed agents.
• Proposed alternative imaging methods (relative RECIST, volumetric, functional imaging) lack sufficient supporting data for routine clinical adoption.
• Limited data exist on using baseline imaging to guide therapy selection.

Conclusions:

• Current imaging techniques and metrics are insufficient for optimal monitoring of targeted therapies in metastatic renal cancer.
• Alternative imaging modalities and baseline characteristic analysis require further research before routine clinical implementation.
• A combination of standard cross-sectional imaging and clinical judgment remains the most practical approach for treatment decisions in metastatic renal cancer pending further biomarker development.