Microwave ablation is a feasible alternative to nephrectomy in selected patients with renal cell carcinoma (RCC) tumors that are 4 to 7 cm in diameter, according to investigators.

In a study of 325 patients with clinical T1b RCC—of whom 40, 74, and 211 underwent percutaneous microwave ablation, partial nephrectomy (PN), and radical nephrectomy (RN), respectively—estimated 5-year local recurrence-free survival (LRFS) was 94.5% for microwave ablation compared with 97.9% for PN and 99.2% for RN. The difference in LRFS between microwave ablation and RN was significant, but the differences between microwave ablation and PN and between PN and RN were not.

Two patients experienced recurrence after microwave ablation and underwent repeat ablation without subsequent recurrence, a team led by E. Jason Abel, MD, of the University of Wisconsin School of Medicine in Madison, reported in Urology. Five-year metastasis-free survival and cancer-specific survival did not differ among the treatment arms.

The rate of local recurrence was 1.2% (4 patients) overall. The rate was 5% in the microwave ablation group, 1.4% in the PN group, and 0.5% in the RN group.

No patient in the microwave ablation group died from RCC, but 3 PN patients (4.1%) and 12 RN patients (5.7%) died from RCC at a median of 123.6 months and 61.7 months, respectively.

The median length of hospitalization was shorter for the microwave ablation group than the PN and RN patients: 1 day vs 4 days and 4 days, respectively. The blood transfusion rate was not significantly different among the treatment arms.

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In addition, the estimated glomerular filtration rate (eGFR) at 3 months postoperatively decreased by a median of 4.5% in the microwave ablation group, 3.2% in the PN group, and 29% in the RN group. The change in eGFR did not differ significantly between the microwave ablation and PN patients, but the reduction in eGFR in the RN group was significantly greater than in the other 2 groups.

Reference

Shapiro DD, Wells SA, Best SL, et al. Comparing outcomes for patients with clinical T1b renal cell carcinoma treated with either percutaneous microwave ablation or surgery [published online October 1, 2019. Urology.  doi: 10.1016/j.urology.2019.09.024