Comparison of Percutaneous Cryoablation and Microwave Ablation for Treatment of Renal Masses

Monday, March 6, 2023

3:09 PM – 3:18 PM

Location: Phoenix Convention Center, 221AB

Presenting Author(s)

Shawdon Molavi, MD (he/him/his)

Interventional Radiology Independent Resident
Christiana Care

Disclosure(s): No financial relationships to disclose

Author/Co-author(s)

WR

William Ryan, MD

Resident
ChristianaCare
BL

Brady Laughlin, DO

Attending Physician
Summit Radiology
Daniel A. Leung, MD, FSIR

Professor, Program Director
Christiana Care Health Services
CG

Christopher J. Grilli, DO

Attending Physician
Christiana Care
Assaf Graif, MD (he/him/his)

Attending Physician
Christiana Care

Disclosure(s):

Shawdon Molavi, MD: No financial relationships to disclose

Daniel A. Leung, MD, FSIR: Boston Scientific: Consultant (Ongoing), Speaking and Teaching (Ongoing); Cook: Speaking and Teaching (Ongoing)

Assaf Graif, MD: Boston Scientific, Inc.: Advisory Committee or Review Panel Member (Ongoing)

Purpose: To compare the effectiveness and safety percutaneous Cryoablation (Cryo) and of microwave ablation (MWA) for the treatment of renal masses.

Materials and Methods: A retrospective review was performed of renal mass ablation procedures between 2008 and 2020, which found 245 Cryo procedures and 94 MWA procedures (Age: 67.4±12.9 vs. 67.8±11.3 years, p=.8, Female: 37.6% vs. 34%, p=.6, respectively). Among these, there were 76 cryo procedures and 45 MWA procedures that were performed for biopsy proven renal cell carcinoma (RCC) (Age: 69.4±10.7 vs. 66.5±11.3 years, p=.2, Female: 26.3% vs. 28.9%, p=.8, respectively). The mRENAL and MC2 scores were similar between both groups, including between the proven RCC subgroups. Technical success was defined as the ablation zone encompassing mass and >5mm margin, and along with adverse events, was reported for the entire cohort. Primary technical success (defined as no residual enhancement on first follow-up imaging) and time local progression were calculated for the RCC cohort.

Results: The technical success rate was similar (94.3% vs. 97.9%, p=.3) when comparing the entire cohort for Cryo and MWA, respectively, and in the RCC subgroups (93.4% vs. 97.8%, p=.4). Mean follow-up duration was 28.4±24.6 months for Cryo and 33.5±19.2 months for MWA (p=.2). Primary technical success was significantly higher (p=.049) with MWA (97.7%) than for Cryo (85.5%). The time to local progression was 74.8 months for a single patient in the Cryo RCC group. Reintervention rate for residual tumor or recurrence was higher in the Cryo RCC group than the MWA RCC group (12.5% vs. 2.3%, p=.09). The Cryo group had significantly more hemorrhagic complications (within 30 days of procedure) than the MWA group (25/239 (10.5%) vs. 3/94 (3.2%), p=.03). Injury to the collecting system occurred more commonly in the MWA group (6.4% vs. 2.1%, p=.08). Procedure related readmission rate was similar in the Cryo and MWA groups (4.1% vs. 4.3% respectively, p=.7).

Conclusion: Percutaneous microwave ablation appears to have higher primary technical success, possibly resulting in less reinterventions for residual or recurrent RCC lesions. MW ablation resulted in more collecting system injuries but less hemorrhagic complications.