Initial Experience Using Microwave Ablation Therapy for Renal Tumor Treatment: 18-Month Follow-up

• Published in: Journal of endourology 2011-04, Vol.77 (4), p.792-797
• Main Authors: Castle, Scott M, Salas, Nelson, Leveillee, Raymond J
• Format: Article
• Language: English
• Subjects: Ablation (Surgery); Ablation Techniques; Aged; Aged, 80 and over; Biological and medical sciences; Carcinoma, Renal Cell - diagnostic imaging; Carcinoma, Renal Cell - pathology; Carcinoma, Renal Cell - therapy; Care and treatment; Diagnosis; Diathermy - methods; Female; Follow-Up Studies; Humans; Kidney Neoplasms - diagnostic imaging; Kidney Neoplasms - pathology; Kidney Neoplasms - therapy; Kidneys; Laparoscopy; Male; Medical sciences; Microwaves - therapeutic use; Middle Aged; Necrosis; Nephrology. Urinary tract diseases; Tomography, X-Ray Computed; Treatment Outcome; Tumors; Tumors of the urinary system; Urology
• ISSN: 0090-4295; 0892-7790; 1527-9995
• DOI: 10.1016/j.urology.2010.12.028

Objectives To assess efficacy and morbidity of microwave ablation (MWA) for small renal tumors in an initial cohort of patients. MWA is a recently introduced thermal needle ablation treatment modality with theoretical advantages compared with radiofrequency ablation, such as greater intratumoral temperatures, lack of a grounding pad, and superior convection profile. However, experience has been limited in the human kidney. Methods Ten patients with a single, solid-enhancing renal tumor from June 2008 to November 2008 received laparoscopic or computed tomography-guided percutaneous MWA at a tertiary referral center with ≥14 months of follow-up. MWA was performed using the Valleylab Evident, 915-MHz MWA system at 45 W with intraoperative biopsy before ablation, and peripheral fiberoptic thermometry to determine the treatment endpoints. The patients were followed up with contrast-enhanced computed tomography at 1 month, 6 months to 1 year, and annually to monitor for tumor recurrence. Results The follow-up duration for the 6 male and 4 female patients (mean tumor size 3.65 cm, range 2.0-5.5; mean age 69.8 years) was 17.9 months. The recurrence rate, defined by persistent enhancement, was 38% (3 of 8). The intraoperative and postoperative complication rate was 20% and 40%, respectively. Conclusions MWA resulted in poor oncologic outcomes with a significant complication rate at an intermediate level of follow-up. However, MWA has promising theoretical advantages and should not be discarded. Additional studies should be considered to better understand the microwave-tissue interaction and treatment endpoints for different size renal masses before widespread use.