OBJECTIVETo investigate clinical outcomes of ultrasound-guided percutaneous radiofrequency ablation (USG-RFA) in patients with renal clear cell carcinoma.

METHODSMedical records of 34 patients who underwent USG-RFA of renal clear cell carcinoma at the Department of Urology of the Affiliated Drum Tower Hospital of Medical School of Nanjing University from May 2009 to January 2014 were retrospectively reviewed, including 28 male and 6 female patients aged between 25 and 85 years (mean age 60.7 years). Of the included cases, 16 had tumors located in the left kidney, 16 in the right, 1 in the solitary kidney, and 1 in the bilateral kidney. There were 35 tumors in this study totally. The maximum diameter of the tumors was 1.8 to 5.0 cm (mean (2.7 ± 0.3) cm), of which 32 cases of renal tumors were ≤ 4.0 cm and 3 cases of renal tumors were > 4.0 cm to 5.0 cm. Pathological diagnosis were acquired by ultrasound-guided percutaneous biopsy after USG-RFA. Contrast-enhanced ultrasound was used to evaluate tumor outcomes at the time of the surgery, and multi-slice spiral CT enhanced scan and contrast-enhanced ultrasound were used to identify residues and recurrences after treatment.

RESULTSTreatments for all the patients were finished with short postoperative hospital stay about 3-5 days. No complications related to USG-RFA were encountered in any of the cases, such as perirenal fluid collection, perirenal hematoma, and peripheral organ damage. All the cases were diagnosed as clear cell carcinoma according to pathological results. The mean follow-up period was 29 ± 6 (range 3-59) months. Of the 35 USG-RFA-treated subjects, 32 tumors ≤ 4 cm reached the standard of complete treatment after one tumor was found with residue after the first month follow-up, and two tumors were noted recurrence at the 4 and 10 months follow-up after USG-RFA. Nonetheless, no residue or recurrence occurred after secondary treatment for these 3 tumors where pathological diagnosis were acquired again. The other 3 cases with tumors > 4.0 cm to 5.0 cm underwent USG-RFA twice or three times before reaching the standard of complete treatment, of which two had twice and one tumor had three times treatments. There was no carcinoma residue or recurrence during follow-up period.

CONCLUSIONSPercutaneous ultrasound-guided radiofrequency ablation for small renal mass (SRM) has satisfied clinical outcomes, with the advantage of less injury, lower complication rates and shorter recovery time for small size of renal clear cell carcinoma. USG-RFA may become the preferred treatment alternative for SRM.