Rediscovering the indispensable role of FDG PET in kidney cancer imaging

Introduction: This exhibit explores the utility of FDG PET in renal cell carcinoma subtypes. Additionally, the use of FDG in Total Body PET imaging of renal cancer will also be discussed.

Unlike its routine use in imaging of other malignancies, 18F-fluorodeoxyglucose PET/CT has limited application in renal cell carcinoma (RCC). This is due to the kidneys' natural excretion of FDG, which lowers the contrast between renal lesions and normal tissue, potentially obscuring or masking renal tumors. Despite its drawbacks, FDG PET imaging of kidney cancers has certain benefits that are worth investigating. In individuals with recurrent or metastatic RCCs, hybrid PET/CT was demonstrated to have a greater sensitivity and specificity. FDG PET scans have also been demonstrated to be effective in monitoring response to therapy to tyrosine kinase inhibitors (TKIs) in advanced RCC; PET/CT is therefore being utilized more often to assess therapeutic response to TKIs. Additionally, FDG PET has greater sensitivity and accuracy for detecting renal metastases to the bone than a bone scan.

Methods: This exhibit aims to provide an overview of the key conventional and novel applications of FDG-PET in various kidney cancers imaging including the use of FDG-PET in a) primary RCC, b) metastatic RCC c) type II papillary and sarcomatoid d) staging of RCC e) assessing treatment response. Additionally, we will explore the utilization of new technologies such as Total Body PET (TB-PET) that are more sensitive and allow for opportunities for delayed imaging.

Results: Advantages of FDG PET/CT imaging of RCC subtype

FDG PET/CT for prediction prognosis of RCC

Delayed imaging and multi-time point imaging

Beyond multi-time point imaging: Utility of TB-PET in renal cancer dynamic imaging and patlak modeling to extract kinetic information and capture the complete time course of 18F-FDG diffusion throughout the body.

Conclusions: FDG PET/CT is not routinely done in the majority of primary RCCs, however, some RCC subtypes are extremely receptive to the agent. Delayed imaging or multi-time point imaging is also an area that has been explored but currently has low adoption clinically. FDG PET may be beneficial for preoperative staging in high-risk, larger individuals, and is especially useful when conventional non-contrast CT images are negative or there is a suspected acute or subacute tumor thrombus. FDG PET/CT is increasingly being utilized to assess targeted molecular therapy such as Tyrosine Kinase inhibitors (TKI) in metastatic RCC.