CT-guided percutaneous cryotherapy of renal masses.
OBJECTIVE
To assess the results of initial and current techniques for percutaneous renal cryotherapy, including long-term imaging outcomes.


METHODS
Computed tomography (CT)-guided percutaneous cryotherapy was performed on 49 masses in 48 outpatients and procedure comfort noted for each. These 49 masses included 36 primary renal cell carcinomas (RCCs), 3 oncocytomas, 1 angiomyolipoma, 6 renal inflammatory lesions, 2 benign parenchymal changes, and 1 colon cancer metastasis. All complications were graded according to standardized criteria.


RESULTS
Patients received only local anesthesia and moderate sedation during the procedure and were discharged with minimal discomfort within 4-6 hours. All cryotherapy zones were well defined by CT during ablation as hypodense ice with an average diameter of 5.3 cm, covering an average tumor size of 3.3 cm. Average ablation zone diameters showed significant reduction over time (P < .001), becoming significantly less than the original tumor size by 12 months (P < .05). Major and minor complications were seen in 3 (6%) and 11 (22%) procedures, respectively. At a mean follow-up of 1.6 years (range, 1 week to 3.8 years) for primary RCC patients, four failures (11.1%) by imaging criteria were noted, but one proved to be inflammatory tissue at re-biopsy (estimated neoplastic failure rate = 3/36 = 8.3%).


CONCLUSIONS
Percutaneous renal cryotherapy is a well-tolerated outpatient procedure that allows safe, CT monitoring of ice formation beyond visible tumor margins. With appropriate cryoprobe placements, a low failure rate appears less dependent on tumor size or location. Ablation volume involution was >80% after 6 months.
Littrup
Peter J
PJ
Biostatistics Unit, Wayne State University, 110 East Warren, Hudson-Weber Building, Suite 504, Detroit, MI 48201, USA. littrupp@karmanos.org
Ahmed
Abraham
A
Aoun
Hussein D
HD
Noujaim
Daniel L
DL
Harb
Ted
T
Nakat
Sam
S
Abdallah
Khaled
K
Adam
Barbara A
BA
Venkatramanamoorthy
Raghu
R
Sakr
Wael
W
Pontes
J Edson
JE
Heilbrun
Lance K
LK
D000368:Aged; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D015641:Radiography, Interventional / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome