Effects of Thermal Ablation on Diagnostic Interpretation

Thermal ablation (TA) of small renal masses (SRMs) is a well-accepted treatment modality with good long-term oncologic efficacy and low morbidity. Renal mass biopsy (RMB) should be utilized prior to TA to counsel patients and guide surveillance. The role of RMB in post-TA surveillance is poorly defined. TA can stabilize tumor tissue architecture complicating interpretation of histopathology. RMB is recommended, however, for patients in which axial imaging demonstrates a concern for tumor recurrence. Radiographic imaging is critical for the diagnosis, treatment, and surveillance of SRMs. Imaging is necessary to target the lesion during the procedure and to confirm adequate ablation. Following ablation, persistent or recurrent contrast enhancement is concerning for viable tumor that needs to be treated or observed. Other characteristics such as increasing size, lack of involution, or increasing nodularity in the lesion can also be consistent with malignancy. The goal of this chapter is to outline the role of renal mass biopsy around the time of ablation; implications of imaging prior to, during, and after thermal ablation; monitoring of immediate post-procedure success; and criteria for long-term surveillance.