Tumor location does not impact oncologic outcomes for percutaneous microwave ablation of clinical T1a renal cell carcinoma.
OBJECTIVE
To evaluate the impact of anterior tumor location on oncologic efficacy, complication rates, and procedure duration for 151 consecutive biopsy-proven clinical T1a renal cell carcinoma (RCC) treated with percutaneous microwave (MW) ablation.


METHODS
This single-center retrospective study was performed under a waiver of informed consent. One hundred forty-eight consecutive patients (103 M/45 F; median age 67 years, IQR 61-73) with 151 cT1a biopsy-proven RCC (median diameter 2.4 cm, IQR 1.9-3.0) were treated with percutaneous MW ablation between March 2011 and August 2017. Patient and procedural data collected included Charlson comorbidity index (CCI), RENAL nephrometry score (NS), use of hydrodisplacement, MW antennas/generator output/time, and procedure time (PT). Data were stratified by anterior, posterior, and midline tumor location and compared with the Kruskal-Wallis or chi-squared tests. The Kaplan-Meier method was used for survival analyses.


RESULTS
Tumor size, NS, and use/volume of hydrodisplacement were similar for posterior and anterior tumors (p > 0.05). Patients with anterior tumors had a higher CCI (3 vs 4, p = 0.001). Median PT for posterior and anterior tumors was similar (100 vs 108 min, p = 0.26). Single session technical success and primary efficacy were achieved for all 151 tumors including 61 posterior and 67 anterior tumors. The 4 (3%) Clavien III-IV complications and 6 (4%) local recurrences were not associated with tumor location (p > 0.05). Three-year RFS, CSS, and OS were 95% (95% CI 0.87, 0.98), 100% (95% CI 1.0, 1.0), and 96% (95% CI 0.89, 0.98), respectively.


CONCLUSIONS
The safety and efficacy of percutaneous microwave ablation for anterior and posterior RCC are similar.


KEY POINTS
• The safety profile for percutaneous microwave ablation of anterior and posterior T1a renal cell carcinoma is equivalent. • Percutaneous microwave ablation of T1a renal cell carcinoma provides durable oncologic control regardless of tumor location. • Placement of additional microwave antennas and use of hydrodisplacement are associated with longer procedure times.
['Maciolek|Kim A|KA|', 'Abel|E Jason|EJ|', 'Posielski|Natasza M|NM|', 'Hinshaw|J Louis|JL|', 'Lubner|Meghan G|MG|', 'Lee|Fred T|FT|', 'Ziemlewicz|Timothy J|TJ|', 'Wells|Shane A|SA|http://orcid.org/0000-0002-1067-6624']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D002292:Carcinoma, Renal Cell D017115:Catheter Ablation D005260:Female D006801:Humans D007680:Kidney Neoplasms D008297:Male D008872:Microwaves D008875:Middle Aged D009364:Neoplasm Recurrence, Local D012189:Retrospective Studies
Microwaves Renal cell carcinoma Recurrence Safety