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IMAGE-GUIDED ABLATION OF RENAL TUMORS
Servet Tatli MDAssociate Professor of Radiology
Harvard Medical School
Department of RadiologyBrigham and Women’s Hospital
Objectives
• Review current image-guided ablation techniques used in treatment of renal tumors
• Discuss technical issues that may arise during image-guided ablation of renal tumors with illustrated examples
• Nothing to disclose
Kidney Ablation, rationale• Detection of increasing number of small
incidental RCC’s necessitated development of less invasive treatment options to replace nephrectomy (partial or total)
• Percutenous, image-guided ablation methods are promising alternative techniques and particularly suit patients with– solitary kidney
• nephron sparing ablation
– advanced age – co-morbidities preventing surgery– multiple RCC’s & heritable renal cancer syndromes
Kidney Ablation, tumor selection
• Not suitable patients– uncorrected coagulopathy– acute illness (sepsis)– locally invasive tumors– tumors with metastases
• Challenging tumors– large (> 5cm)– central– anterior location
• Renal tumors more suitable for ablation– small (3cm)– peripheral / exophytic– posteriorly situated– inferior pole
• Role of preablation biopsy
– should be considered– benign masses mimic malignancy on imaging– 1/3 benign (2.2cm) [Tuncali K, AJR 2004]
Kidney Ablation, technical issues• Positioning
– RPO or LPO on most cases
Kidney Ablation, technical issues• Large tumors
Kidney Ablation, technical issues• Large tumors
Kidney Ablation, technical issues• Large tumors
Kidney Ablation, technical issues• Multiple tumors; combine with nephrectomy
Kidney Ablation, technical issues• Multiple tumors; simultaneous ablation in both kidneys
Kidney Ablation, technical issues• Central tumors
Kidney Ablation, technical issues• Central tumors
Kidney Ablation, technical issues• Cystic tumors or a tumor adjacent to a cyst
Kidney Ablation, technical issues• Cystic tumors or a tumor adjacent to a cyst
Kidney Ablation, technical issues• Superior pole tumors
Kidney Ablation, technical issues• Anterior tumors; positioning
Kidney Ablation, technical issues• Anterior tumors; transhepatic approach
Kidney Ablation, technical issues• Anterior tumors; manual displacement
Kidney Ablation, technical issues• Tumors close to bowel; hydrodissection
Kidney Ablation, technical issues• Tumors close to bowel; instillation of room air or CO2
Venkatesan AM, Radiology 2011
Kidney Ablation, technical issues• Lower pole medial tumors
– ureteral stent
Kidney Ablation, technical issues• Nephron sparing ablation
– S/P nephrectomy
Kidney Ablation, technical issues• Nephron sparing ablation
– syndromes (VHL, familial RCC syndromes, Birth-Hogg-Dube)
Kidney Ablation, technical issues• Recurrence / needle tract seeding
Sainini N, Tatli S, JVIR 2013
Kidney Ablation, technical issues• Tumors in transplant kidney
Kidney Ablation, technical issues
• Retroperitoneal renal cell carcinoma metastasis
Kidney Ablation, effectiveness• RFA, 90 /100 (90%) tumors underwent
complete necrosis [Gervais DA, AJR 2005]
• Cryoablation [Tuncali, RSNA 2006]
– 62/63 (97%) secondary effectiveness, 95% in one session
• Meta-analysis for percutaneous vs. surgical approach [Hui, GC, JVIR, 2008]
– primary effectiveness• percutaneous, 87%• surgical, 94%
– secondary effectiveness• percutaneous, 92%• surgical, 95%
Kidney Ablation, effectiveness
Venkatesan AM, Radiology 2011
Kidney Ablation, complications• Few (3.6%) major (bleeding, abscess)
– lower than surgery • percutaneous treatment group (3%)• surgical treatment group (7%) [Hui, GC, JVIR 2008]
• Complications– post-ablation syndrome (low-grade fever, pain, myalgia)– hematuria (self-limited; rarely, bladder obstruction)– perinephric hematoma– thermal injury to adjacent structures
• ureter, genitofemoral nerve, psoas muscle, intestines, adrenal gland
Post-ablation Care– Labs
• CBC– Hct (40-54%), platelet (150-450 /µL ), WBC (4-10 /µL)
• metabolic panel– electrolytes, creatinin (0.5-1.2 mg/dL), BUN, EGFR (>60)
• serum myoglobin (<100 ng/ml)– mark elevation (>1000 μg/L)
» urine alkalinization with sodium bicarbonate» 3 amps of 50 mEq in 1 L of D5W at 150 mL/hr)
– prophylactic alkalinization» treatment of tumors adjacent muscular structures» in patients with poor kidney function Nair RT, Radiology 2008
Post-ablation Care– Next day morning imaging
• MRI, CECT– baseline for follow up imaging
– residual tumor?
– complications?
– Imaging surveillance• (every 3 months for the first year, 6 months for the
second year, and yearly afterwards)• recurrence? • new tumors?• extrarenal disease?
Kidney Ablation, surveillance
• 67 yom left renal cell carcinoma
24 hrs 24 hrs 3 months3 months12 months12 months
• Expected post ablation imaging findings– enhancement of the tumor
Kidney Ablation, postablation surveillance• Granulation tissue mimicking needle tract seeding
• Lokken et al, AJR 2007
Conclusion
• Percutaneous image-guided ablation of kidney neoplasm is safe and effective
• It is minimally invasive treatment option alternative to surgery
• Appropriate patient, ablation method, and guidance modality selection, and post-ablation surveillance are important factors for satisfactory results with fewer complication
Thank you