Killing Tumors with Scans Not Scalpels: Kidney Cancer Ablation. Basics. What is Percutaneous Ablation? Where are your kidneys?

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1 Killing Tumors with Scans Not Scalpels: Kidney Cancer Ablation Ronald J. Zagoria, M.D. UCSF Professor and Vice Chair Abdominal Imaging Section Chief Basics Where are your kidneys? What is ablation? Facts about kidney cancer that influence cancer management choices Where are your kidneys? Kidney function is essential for fluid and metabolite balance. What is Percutaneous Ablation? Percutaneous = Through the skin Ablation = Destruction Cancer is killed, but not removed No incision Tumor becomes dead scar tissue Cannot grow Cannot spread Page 1

2 Typical kidney cancer =Renal cell carcinoma Kidney Cancer Diagnosis-It s all about the imaging! Important Facts About Kidney Cancer Most found incidentally by imaging Grow very slowly, usually Don t spread when small (< 3 cm) High cure rate if no spread Very low cure rate if cancer has spread to other sites Treatment with chemotherapy and radiation is rarely curative Goals of Kidney Cancer Treatment Cure cancer Preserve kidney function Minimize treatment morbidity & mortality Page 2

3 Treatment Options for Early Stage Kidney Cancer Nephrectomy Partial Nephrectomy Laparoscopic Ablation Percutaneous Ablation Surveillance Imaging Surgical Resection Partial and radical nephrectomy equivalent for small tumors 5 year disease-free survival >90% Local recurrence rate 3% Metastases 6% Surgical Resection Proven procedure with high cure rate, but. Significant morbidity >20% of radical nephrectomy patients eventually develop kidney insufficiency* *Correlation with shortened lifespan Resection vs. Ablation Have equivalent rates of tumor cure, > 90%, for small kidney tumors Small kidney tumor is < 4cm diameter (about 1.5 inches) Page 3

4 Treatment of Kidney Tumors: Surgery vs. Percutaneous For small kidney tumors, cure rate is equivalent Surgery has substantially higher morbidity, and costs. Relatively limited long term follow-up data raises some uncertainty about long term equivalence Ranking Treatment Options for Early Stage Kidney Cancer 1. Partial Nephrectomy 1. Percutaneous Ablation 1. Surveillance Imaging Reserve for elderly & infirmed 2. Nephrectomy Reserve for large tumors 3. Laparoscopic Ablation Almost never Ablation Techniques Heat (cooking) Radiofrequency ablation (RFA) Microwave ablation (MWA): Early data, but probably equivalent Freezing Cryoablation Page 4

5 Page 5 Cryoablation: how it works

6 Kidney Ablation Results Neither tumor position nor location influenced ablation success rate* Central tumors less effectively eradicated: 91% vs. 100%** *Zagoria R et al. AJR August, 2007 ** Gervais D, et al. RSNA 2008 Percutaneous Kidney Tumor Ablation Results In Patients Authors # Tumors Success Charboneau 145 Mayo-Smith 32 Gervais 306 Pavlovich 24 Varkarakis 56 Farrell 35 Memarsadeghi 24 Stern 40 Breen 105 Zagoria 125 Total % RFA and Cryoablation Cancer-free rates identical Both minimally invasive Low rate of serious complications Less than 5% for both techniques Technique choice a matter of personal preference Page 6

7 Goal #2: Preserve Kidney Function 1 year follow-up: Minimal ablation of normal kidney Page 7

8 Ablation Effect on Kidney Function* 77 patients treated with percutaneous ablation studied egfr pre-ablation = 52 egfr 12 months post-ablation = 52 RFA effect on Kidney Function Patients with multifocal kidney tumors 169 tumors in 57 patients Mean of 4.4% egfr drop per ablation site Better than published surgery results *Percutaneous radiofrequency ablation does not affect glomerular filtration rate. J Endourol Oct;24(10): How ablation is done: Example 3 cm kidney cancer Biopsy Multiple, short ablations Procedure takes between 1 and 2 hours Rapid recovery Go home next morning Resume activities immediately Usually no further treatment How Ablation is done: 3 cm Renal Cancer Page 8

9 How ablation is done : 3 cm tumor How ablation is done: overlapping ablations, low radiation dose scanning K How ablation is done : Contrast CT Hydrodissection to Protect Colon Tumor ablated Small margin around treated tumor 45 min. procedure Colon Colon Tumor Page 9

10 Evolution of an Ablated Tumor Pre-ablation Immediate post ablation 6 months 5/2003 6/2004 8/ months 2 years 3 years Advanced Cancer: This can be avoided Treatment Option Preferences for Early Stage Kidney Cancer 1. Partial Nephrectomy 1. Percutaneous Ablation 1. Surveillance Imaging Reserve for elderly & infirmed 2. Nephrectomy Reserve for large tumors 3. Laparoscopic Ablation Almost never Conclusions-Percutaneous Thermal Ablation Treatment option for patients with small kidney tumors and no metastases Cure rate ~ resection Risk of serious complications is < 5% (Goal #3) Radiofrequency and cryoablation have equivalent results Long-term follow-up, at least 5 years, is advisable Page 10

11 Kidney Cancer is an Ideal Ablation Site All tumors detectable with imaging Unlike liver where surgery shows more Primary, low stage, solitary tumors Unlike liver, lung Do not metastasize early unlike pancreas cancer Cure is highly likely Post-treatment imaging highly accurate Percutaneous Ablations Also used for treatment of some tumors in liver, bones, lungs, prostate, but choices are more complicated. Not used for widespread disease, or for pancreas, intestines, bladder, or brain. THANKS FOR YOUR ATTENTION RON ZAGORIA, MD Page 11