Iceball Margin ted with Local Failure after CT-guided Cryoablation of cT1a Renal Cell Carcinoma
Materials and methods: Outcomes of PCA for biopsy-proven RCC (2015–2022) with ≥12 months of imaging follow-up were retrospectively reviewed. LTF was defined as residual tumor or local progression. MTM, defined as iceball extension beyond tumor margins, was measured on spatially synchronized intraprocedural and planning CTs. LTF cases were matched 1:2 to local controls by size and histology. Diagnostic performance was evaluated using receiver operating characteristic analysis in the matched cohort.
Results: Of 575 RCCs, 17 (3.0%) demonstrated LTF. Median follow-up was 1,173 days. Tumors with LTF were significantly larger than tumors with local control (29.2 vs. 23.7 mm; P = 0.01), and MTM was significantly smaller in the LTF group (0.4 vs 7.1 mm; P < 0.001). Receiver operating characteristic analysis within the matched analytical cohort demonstrated high discrimination for stratifying local failure risk (AUC = 0.97). The predefined 5-mm clinical threshold, defined as MTM <5 mm indicating an insufficient margin, achieved the maximal Youden index, with sensitivity and specificity of 88.2% and 94.1%, respectively. All in-zone failures occurred with MTM <5 mm; two out-of-zone progressions occurred adjacent to Gerota’s fascia despite MTM ≥5 mm.
Conclusion: LTFs after PCA of T1a RCC were associated with insufficient (<5 mm) iceball margins. Achieving an MTM ≥5 mm is strongly associated with durable local control, underscoring the importance of careful intraprocedural assessment of margins.
Jens Borgbjerg, MD PhD, Mia Gebauer Madsen, MD PhD, Rozh Al-Mashhadi, MD PhD, Gratien Andersen, MD, Simone Buchardt Brandt, MD PhD, Theresa Junker, RN PhD, Nis Elbrønd Larsen, MD, Marte Leland-Try, MD, Casper Riis Therkildsen, MD, Ole Graumann, MD PhD
Akershus University Hospital, Norway; Aarhus University Hospital, Denmark; Odense University Hospital, Denmark; Gødstrup Hospital, Denmark
Source: Borgbjerg J, Madsen M, Al-Mashhadi R. et al. Iceball Margin <5 mm Is Associated with Local Failure after CT-guided Cryoablation of cT1a Renal Cell Carcinoma. Journal of Vascular and Interventional Radiology. 2026. DOI: 10.1016/j.jvir.2026.108905.