Outcomes of Percutaneous Ablation of Synchronous and Metachronous Small Renal Masses (SRM)

Monday, March 6, 2023

12:00 PM – 1:00 PM

Location: Phoenix Convention Center, North Ballroom 120 D

Poster Presenter(s)

PL

Patrick Lee, MD

Integrated Diagnostic and Interventional Radiology Resident
Thomas Jefferson University

Disclosure(s): No financial relationships to disclose

Author/Co-author(s)

George Sun, BS

Medical Student
Sidney Kimmel Medical College at Thomas Jefferson University
Philip Lee, MD

Resident
Mount Sinai
CB

Clayton Brittingham, DO

Interventional Radiology Fellow
Thomas Jefferson University
CS

Colette Shaw, MD

Section Chief, Interventional Radiology
Piedmont Hospital

Disclosure(s):

Patrick Lee, MD: No financial relationships to disclose

Purpose: To evaluate the safety, efficacy, and outcomes of percutaneous ablation of synchronous or metachronous SRM.

Materials and Methods: A single-center retrospective review of percutaneous ablations of SRM performed between 2010 and 2021 was performed. Patients who underwent ablation of more than one kidney lesion, either in a single or multiple encounter(s), were included. Lesions were limited to T1a or T1b. Patients with metastatic disease at presentation or treatments for recurrence were excluded. Wilcox rank sum test was used to compare pre- and post-ablation creatinine. Kaplan-Meier analysis was performed to assess overall survival (OS) and cancer specific survival (CSS) from index ablation.

Results: A total of 54 lesions were ablated in 24 patients (22 males) across 40 encounters. Nineteen patients had two, four patients had three, and one patient had four lesions treated. The mean ± SD lesion diameter was 2.5 cm ± 1.0 cm and the median lesion nephrometry score was 6 (range 4-10). The majority of lesions were right-sided (n=32, 59%). Mean ± SD patient age was 69 ± 2.1 years and median Charlson Comorbidity index was 6 (range 2-10) at the time of treatment. Biopsy was performed for 45 lesions (83%) with malignancy present in 30. Ablation techniques were cryoablation (n=22, 41%) and microwave ablation (n=32, 59%). Median number of probes placed per lesion was 2 (range 1-5). Pyeloperfusion was performed for 3 lesions (6%) and hydrodissection for 15 (28%). Technical success was achieved in 100%. Median length of hospital stay was 1 day (range 0-7 days). Major complication occurred in one patient (Society of Interventional Radiology (SIR) class D) who suffered an acute ischemic stroke requiring extended hospitalization. Minor complication (SIR class B) occurred in one patient who had subcapsular hematoma managed conservatively. There was a statistically significant increase in creatinine 3-12 months following ablation (1.9 to 2.1 mg/dL, p=0.009). However, no patients required subsequent hemodialysis initiation. Follow-up imaging was obtained in 23 patients (96%) with no instances of residual disease or local recurrence. Mean ± SD follow-up time was 4.6 ± 4.0 years. The 5-year OS was 80% for both the entire cohort and the subset of patients with documented malignancy on biopsy (n=17). CSS was 96% for the entire cohort. A single patient died from complications related to metastatic renal cell carcinoma.

Conclusion: Percutaneous ablation of synchronous or metachronous SRM demonstrated similar safety, efficacy, and outcomes compared to historical data for ablation of a solitary lesion.