# Long-term oncological outcomes following percutaneous microwave ablation of T1 renal cell carcinoma

## TL;DR

This study shows that microwave ablation is a safe and effective treatment for small kidney tumors, with low complication rates and good long-term cancer outcomes.

## Contribution

The study provides long-term oncological outcomes for microwave ablation in treating T1 renal cell carcinoma, supporting its use as a treatment option.

## Key findings

- Microwave ablation had low complication rates (0.96% Clavien-Dindo grade ≥III) and short hospital stays.
- Local and metastatic recurrence rates were 5.9% and 2.7%, respectively, over a median 37-month follow-up.
- MWA is safe and effective for biopsy-proven T1 RCC <5 cm, with favorable oncological outcomes.

## Abstract

Incidence of small renal masses (SRMs) including renal cell carcinoma (RCC) is increasing. Standard of care is to offer partial nephrectomy (PN), with tumour ablation (TA) considered an alternative in frail/co-morbid patients. This study aimed to determine whether microwave ablation (MWA) is a safe and effective treatment for selected cases of RCC.

All MWAs performed at a regional tertiary care centre between October 2016 and April 2024 were prospectively recorded on a database. Data collected included tumour and patient characteristics, complications, and recurrences.

Two hundred and nine MWAs were recorded with median 37 months (interquartile range [IQR] 15.3-59.4 months) follow-up. About 94.7% of patients had ≥12 months of follow-up. The biopsy rate was 92%. Following MWA, 93% of patients had a hospital stay of 1 night. Two Clavien-Dindo grade ≥III complications occurred within 30 days (0.96%). Local and metastatic recurrence rates were 5.9% and 2.7%, respectively.

MWA was a safe, effective treatment for SRMs in this large cohort which included young, fit patients and underwent long-term follow-up. Recovery times were short, with low complication rates and favourable oncological outcomes in biopsy-proven T1 RCC <5 cm.

The current study demonstrates a large, diverse MWA cohort (including T1b tumours) with high biopsy rate, minimal loss to follow-up, and long follow-up period facilitating assessment of long-term oncological outcomes in biopsy-proven RCC. The results support MWA as a safe, effective treatment for cT1a RCC that should be offered to patients as part of shared decision making.