Article
Renal Ablation
Dr. Chris Beck • Updated Jan 2, 2024
Renal ablation is a minimally invasive procedure used to treat kidney tumors or abnormal growths by destroying the targeted tissue using heat, cold, or other energy sources. This technique, often performed under imaging guidance, involves the use of radiofrequency ablation, microwave ablation, or cryoablation to precisely target and destroy cancerous cells within the kidney. Renal ablation offers a less invasive alternative to traditional surgery, making it suitable for patients with small kidney tumors or those who are not candidates for surgery due to underlying health conditions. This procedure provides effective treatment with a shorter recovery time, helping to preserve kidney function while effectively managing kidney cancer.
Table of Contents
Pre Renal Ablation Procedure Prep
Renal Ablation Procedure Steps
Post-Procedure
Pre Renal Ablation Procedure Prep
Indications
Renal cell carcinoma:
• American Urological Association supports thermal ablation for T1a tumors which is <4 cm
• < 4 cm can be curable with one treatment
• T1b tumors: >4 cm but <7 cm - usually requires more probes and/or staging of the procedure
• Stage IV disease of metastasis who are not surgical candidates
• Slow growing tumor: on average, grows ~3 mm/year
• Rare to have metastasis when primary <4 cm
Contraindications
• Life expectancy <12 months
• Uncorrectable coagulopathy
• No safe percutaneous window
• Invasion of renal vein or regional lymph node involvement- advanced stage.
• Active infection
Things to Check
• History and physical
• Labs- creatinine, INR, platelets
• Prior imaging- CT and/or MRI
• Consent for renal ablation procedure and anesthesia
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Episode # 536 • 23 Apr 2025
Multidisciplinary Approaches to Renal Cancer Care
This week we bring together urologists and radiologists to work towards a shared goal of innovating on kidney cancer care. Dr. Jason Abel, Professor of Urology and Radiology at the University of Wisconsin, and Dr. Louis Hinshaw, Section Chief of Abdominal Imaging Intervention at the University of Wisconsin, join our host Dr. Ruchika Talwar for a multidisciplinary conversation regarding the treatment of renal tumors.
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Renal Ablation Procedure Steps
Thermal Ablation Techniques
• Cryoablation
• RFA
• Microwave
Data suggests RFA and cryoablation are similar in efficacy
Data on microwave is less robust
Cryoablation using combination CT and US guidance described below:
Positioning: prone or decubitus
Perform preliminary CT to confirm lesion position, size and adjacent structures.
Test probes in bowl or test tube of normal saline
Ultrasound Guidance for Initial Probe Positioning
• For many patient's US guidance can be faster and more efficient for placement
• Helps evaluate the tumor in 3-D plane
• If using multiple probes, try and keep probes parallel
Once probes in final position using US guidance, confirm positioning with CT
• Evaluate probe position within the tumor
• Evaluate probe position with regards to adjacent structures: renal pelvis, ureter, lung, diaphragm, bowel, adrenal
• Evaluate ablation zone: 5-10 mm (consider full 10 mm margins if feasible)
• Probes no more than 2 cm apart
Opportunity to use protective maneuvers if needed such as hydrodissection
Ablate
• Cycles may vary with manufacturer
• 10 minute freeze with 8 minute active thaw - 2 cycles
• See cell death at -20° C
• Can visualize "ice ball" during freeze cycle
• Can turn on and off probes during freeze cycles to sculpt ablation zone
Remove probes when temperature reaches 10° C
Ice Ball
• Seen at 0°C
• Approximates ablation zone; does not perfectly delineate lethal ablation zone
• Lethal isoderm is 2-3 mm within the ice ball
Post-Procedure
Complications
• Flu-like symptoms (post-ablation syndrome) - fever, fatigue, myalgia. Manage conservatively with antipyretics. Common
• Hemorrhage
• Bowel injury
• Abscess formation/Infection
• Ureteral injury or stricture
• Genitofemoral nerve: anterolateral surface of psoas
• Lower intercostal nerve
Post-Procedural Care
• Monitor patient for at least 2 hours
• Monitor for pain, bleeding, and adjacent structure injury such as pneumothorax
• Discharge home same day if hemodynamically stable, voiding and tolerating po intake
• Discharge medications: anti-inflammatories, antiemetics, and opioids for breakthrough pain
• Most patients will feel back to baseline within 8-10 days
Follow-Up
• Clinic visits with imaging before clinic
• Surveillance can vary
• Consider CT/MR at 3 and 6 months
• If disease free at 6 months, CT/MR at 12, 18 and 24 months
• If disease free at 24 months, CT/MR at 3, 4 and 5 years
Outcomes
• T1a lesions treated with ablation similar to partial and radical nephrectomy
• > 95% cancer-specific 5 year survival with thermal ablation
• ~90% overall survival at 5 years with thermal ablation
Additional resources
[1] Xing M, Kokabi N, Zhang D, Ludwig JM, Kim HS. Comparative Effectiveness of Thermal Ablation, Surgical Resection, and Active Surveillance for T1a Renal Cell Carcinoma: A Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked Population Study. Radiology. 2018;288(1):81‐90. doi:10.1148/radiol.2018171407
[2] National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) Kidney Cancer. Version 3.2018.
[3] Pierorazio PM, Johnson MH, Patel HD, et al. Management of Renal Masses and Localized Renal Cancer: Systematic Review and Meta-Analysis. J Urol. 2016;196(4):989‐999. doi:10.1016/j.juro.2016.04.081
[4] Gunn AJ, Gervais DA. Percutaneous ablation of the small renal mass-techniques and outcomes. Semin Intervent Radiol. 2014;31(1):33‐41. doi:10.1055/s-0033-1363841
[5] Uppot RN, Silverman SG, Zagoria RJ, Tuncali K, Childs DD, Gervais DA. Imaging-guided percutaneous ablation of renal cell carcinoma: a primer of how we do it. AJR Am J Roentgenol. 2009;192(6):1558‐1570. doi:10.2214/AJR.09.2582
[6] BackTable, LLC (Producer). (2017, November 1). Ep 15 – Renal Ablation Therapies [Audio podcast]. Retrieved from https://www.backtable.com/shows/vi
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