Comparing Outcomes for Patients with Clinical T1b Renal Cell Carcinoma Treated With Either Percutaneous Microwave...

To compare perioperative and oncologic outcomes for patients with clinical T1b renal cell carcinoma following treatment with microwave ablation (MW), partial nephrectomy (PN), or radical nephrectomy (RN).

Comprehensive clinical and pathologic data were collected for nonmetastatic renal cell carcinoma patients with cT1b tumors following MW, PN, or RN from 2000 to 2018. Local recurrence-free, metastasis-free, cancer-specific and overall survival were estimated using Kaplan-Meier method. Prognostic factors for complications and survival were determined using logistic regression and Cox hazard models, respectively.

A total of 325 patients (40 MW, 74 PN, and 211 RN) were identified. Patients treated with MW were older with higher Charlson comorbidity indices compared to surgical patients. Median length of hospitalization was shorter for MW compared to surgical patients (1 day vs 4 days, P <.0001). Post-treatment estimated glomerular filtration rate decreased by median 4.5% for MW compared to 3.2% for PN (P = .58) and 29% for RN (P <.001). Median follow-up was 34, 35, and 49 months following MW, PN, and RN, respectively. Estimated 5-year local recurrence-free survival was 94.5% for MW vs 97.9% for PN (P = .34) and 99.2% for RN (P = .02). Two patients recurred after MW and underwent repeat ablation without subsequent recurrence. No difference in 5-year metastasis-free survival or cancer-specific survival was found among MW, PN, or RN. Four (10%) MW patients had high-grade complication. Only prior abdominal surgery predicted high-grade complication (OR 6.29, P = .017).

Microwave ablation is a feasible alternative to surgery in select comorbid patients with clinical T1b renal cell carcinoma.