Tommy Kjærgaard Nielsen

CT contrast enhancement following renal cryoablation – artefact or treatment failure?

Publikation: KonferencebidragKonferenceabstrakt til konferenceForskningpeer review

Introduction and objective: Renal cryoablation is a valid treatment option for localized pT1a renal cancer. Treatment success is typically defined as absence of contrast enhancement (CE) and a decrease in size of the cryoablated renal mass (i.e. cryolesion) on follow-up imaging. We investigated the CT characteristics and treatment outcome of renal cryolesions demonstrating CE during postoperative follow-up. Material and methods: A retrospective review of Aarhus Cryoablation Register identified 113 patients with a pT1a biopsy verified malignant renal lesion who underwent primary laparoscopic (LCA) or percutaneous cryoablation (PCA) from August 2005 to August 2012 at Aarhus University Hospital. Six patients were excluded from analysis due to MRI follow-up. During routine postoperative CT follow-up, contrast enhancement of the cryolesion was identified in 34 of the 107 patients (32%). Results: Mean patient age was 64 (45:79) yr. Mean tumour size was 24 (10:43) mm. RCC- subtypes: Clear cell (79 %), Papillary (12 %), Chromophobe (6%), Collecting duct carcinoma (3%). Treatment modalities was: LCA 53% and PCA 47%. A total of 31 patients (29%) were found to have CE on the initial follow-up CT and additional 3 patients had delayed CE (defined as no CE on prior CT). No significant difference in patient characteristics between patients with or without CE lesions was found. Spontaneous resolution of the CE was observed in 15 of the 34 patients (44%). Ten patients (29%) with CE lesions underwent re-ablation, with a median time to re-ablation of 12 months (1-27) after initial procedure. Other salvage procedures was: partial nephrectomy (1 pts), nephrectomy (2 pts) and oncological treatment (4 pts). Stratified on final outcome (spontaneous resolution vs. salvage therapy) age, tumour size, PADUA- score and level of contrast enhancement was significantly (p<0,05) lower among patients experiencing spontaneous resolution. Histology, change in cryolesion size, contrast enhancement pattern and number of cryoprobes used were not significantly different between the two groups. In patients where attenuation levels excited 39 HU it was found that only 13% experienced spontaneous resolution compared to 39% of patients with lower attenuation levels (p=0.004). None of the tumours with a high PADUA-score (≥10) resulted in spontaneous resolution. Conclusion: Early re-treatment prior to 12 months should be carefully evaluated, as spontaneous resolution is commonly observed during postoperative follow-up. The importance of change in cryolesion size remains controversial and requires further research. If the PADUA score is ≥10 and attenuation levels exceed 39 HU on contrast enhancement CT, residual unablated tumor should be considered.
StatusUdgivet - 2014
BegivenhedDansk Urologisk Selskab: Forårsmøde 2014 - , Danmark
Varighed: 28 mar. 201428 mar. 2014


KonferenceDansk Urologisk Selskab

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