Is there a role for perfusion imaging in assessing treatment response following ablative therapy of small renal masses—A systematic review

S.J Withey,J Gariani,K Reddy,D Prezzi,C Kelly-Morland,S Ilyas,A Adam,V Goh

doi:10.1016/j.ejro.2018.07.002

Abstract

AimsAblation therapies are an innovative nephron-sparing alternative to radical nephrectomy for early stage renal cancers, although determination of treatment success is challenging. We aimed to undertake a systematic review of the literature to determine whether assessment of tumour perfusion may improve response assessment or alter clinical management when compared to standard imaging. Material and MethodsTwo radiologists performed independent primary literature searches for perfusion imaging in response assessment following ablative therapies (radiofrequency ablation and cryotherapy) focused on renal tumours. Results5 of 795 articles were eligible, totaling 110 patients. The study designs were heterogeneous with different imaging techniques, perfusion calculations, reference standard and follow-up periods. All studies found lower perfusion following treatment, with a return of ‘high grade’ perfusion in the 7/110 patients with residual or recurrent tumour. One study found perfusion curves were different between successfully ablated regions and residual tumour. ConclusionsStudies were limited by small sample size and heterogeneous methodology. No studies have investigated the impact of perfusion imaging on management. This review highlights the current lack of evidence for perfusion imaging in response assessment following renal ablation, however it suggests that there may be a future role. Further prospective research is required to address this.

Highlights

In 2014, there were 12,523 new cases of renal cancer in the UK [1], a number increased by 78% since the 1990s [1]
Comparing percutaneous RFA to partial nephrectomy (PN) of small renal masses, RFA has been shown to be associated with less blood loss, smaller post-procedure drop in renal function and shorter length of hospital stay [4,5,6]
We identified primary studies investigating perfusion imaging after ablation of small renal masses from the PubMED database

Summary

Introduction

In 2014, there were 12,523 new cases of renal cancer in the UK [1], a number increased by 78% since the 1990s [1] This can be partly attributed to the increased use of cross-sectional imaging and the consequent incidental finding of small, localised renal masses. As incidental small renal masses have been shown to be generally of lower grade and associated with longer disease-free survival than their symptomatic counterparts [2], nephron-sparing treatments have become preferable to conserve renal function. An alternative to PN is ablative therapy either using high (radiofrequency ablation, RFA; microwave ablation) or low temperatures (cryotherapy). These techniques are suited to patients with co-morbidities leading to high surgical or anaesthetic risks, poor renal function or a solitary kidney. Medium term outcomes are comparable with no statistical difference in 5 year tumour-related survival or local recurrence [5,6,7,8]

Methods

Results

Conclusion