Radio-frequency ablation helps preserve nephrons in salvage of failed microwave ablation for a renal cancer in a solitary kidney
The patient presented in this case report was a 63-year-old male with a previous history of papillary renal cell carcinoma (RCC) of Fuhrman Grade of II for which he received a left radical nephectomy at age 51 in an outside facility. He presented with a 4.33-cm lower pole tumor of his solitary right kidney diagnosed via contrast-enhanced computed tomography (CT) scan [] and came to our facility for evaluation. In addition to previous RCC, this patient had an age-adjusted Charlson Comorbidity Index of 5 and a preoperative creatinine of 1.01 with an estimated glomerular filtration rate (eGFR) of 79 ml/min using the modification of diet in renal disease (MDRD) calculation. Treatment options including tumor extirpation and surveillance were offered as alternatives, and the risk and benefits of MWA were discussed with the patient.\nA transperitoneal approach was used. After exposure of the kidney and localization of the tumor, two 13-gauge, 3.7-cm MWA surgical antennae (Covidien, Valleylab, Boulder, CO, USA) were introduced through separate incisions. Fiber-optic thermal sensors were placed at the tumor periphery via visual and ultrasound (US) guidance utilizing a coaxial guide needle with radiopaque sheath (Huey, Cook Vascular, Inc., Vadergrift, PA, USA). Prior to ablation with the antenna(e) in place, a spring-loaded 16-gauge biopsy needle was utilized to take multiple biopsies under visual and US guidance. The microwave antenna was advanced into the tumor [] and MWA commenced with simultaneous peripheral fiber-optic thermometry (Lumasense, Santa Clara, CA, USA) to determine treatment endpoints of >60°C. The microwave system used was the ValleyLab Evident® 915 MHz MW ablation system (Covidien Inc., Boulder, CO, USA) with two 13-gauge, 3.7-cm tip antenna(e) driven at 45 W. Ablation was performed for 23 min at 45 W over three separate deployments. This was based on when the tumor periphery temperatures reached the target temperature as in the techniques previously published.[] Tumor biopsy showed papillary type RCC, Fuhrman grade II.\nThe patient had an uneventful postoperative course, and was followed with a contrast-enhanced CT scan at 1 month [] and at 4 months []. The scan performed at 4 months post-op showed nodular thickening with enhancement at the ablation site read as recurrence [].\nA transperitoneal approach was used. The procedure was performed using the same method as described above. Three 3.0-cm Cooltip® RFA probes (Covidien Inc.) were positioned in a triangular array with peripheral thermometry as described above []. Ablation was performed for a total of 31 min with all peripheral thermometry exceeding 60°C. Tumor biopsy at that time showed unspecified RCC. The patient had an uneventful postoperative course and was followed with a 1-month, 11-month, and 24-month clinical follow-up with 4-phase contrast-enhanced CT scan showing no enhancement of the tumor ablation site and no evidence of recurrent disease. Creatinine values pre-MWA, post-MWA, and post-RFA were 1.01, 1.14, 1.17 mg/ml, respectively. This represents a change in eGFR from 79 to 67 ml/min post-MWA (decreased 15%), and no change post-RFA.