Login to Access Video or Poster Abstract: MP100-18
Sources of Funding: None

Introduction

Cryoablation (CA) is an alternative treatment for small renal cell carcinomas (RCC), although some prior studies lack biopsy data or long term follow-up. We sought to identify risk factors for treatment failure of biopsy-proven RCC following CA as primary treatment at a single institution.

Methods

Comprehensive data were reviewed for 89 patients with biopsy-proven T1 renal cancer who underwent CA as primary treatment between 2003 - 2012. The Kaplan Meier method was used to estimate recurrence-free survival (RFS) from the date of treatment to recurrence, progression, or most recent imaging. A multivariable Cox model was used to evaluate associations with survival.

Results

All tumors were biopsy proven RCC and 62/89 (70%) were clear cell subtype. Median tumor size was 2.6 cm (IQR 2.1 - 3.1) and median follow-up was 50.7 months (IQR 26.1 - 65.6). Overall 5-year survival was 48/57 (82%). Five-year cancer specific survival was 56/57 (98%). Five-year RFS was 89.1% overall. Of 10 CA failures, 9 (90%) tumors recurred locally and 1 progressed to metastatic disease. Mean tumor size among the successful treatment group was 2.63 cm versus 3.28 cm for the treatment failure group (p = 0.05) and all failures were clear cell subtype (p < 0.05). Secondary treatments included: repeat ablation 7/10, nephrectomy 2/10 and systemic therapy 1/10. On Cox multivariate analyses, increased risk of recurrence was associated with tumor diameter (HR = 1.751, p = 0.01). Age, BMI, creatinine, presence of solitary kidney, and history of previous ablation were not associated with recurrence. Median time until recurrence for tumors ≥3.0 cm was 9.9 months and 18.1 months for tumors <3.0 cm, (p = 0.38).

Conclusions

Cryotherapy provides durable treatment of RCC smaller than 4cm. Success of treatment inversely correlates to tumor size. Most treatment failures were successfully treated with repeat ablation.

Funding

None