Assessment of Viable Tumour Tissue Attached to Needle Applicators after Local Ablation of Liver Tumours

Abstract

Aim: Local recurrence and needle track seeding are serious complications after local ablation for liver malignancies and potentially affect long-term survival. The aim of this study was to assess the incidence of viable tissue adherent to the needle applicators after ablation to gain insight into the possible mechanisms of local recurrence and needle track seeding. Methods: A total of 40 consecutive patients underwent 59 local liver ablations. Cells and tissue attached to the needle applicators were analysed for morphology (HE, PAP and Giemsa staining) and viability (G6PD staining). Results: Macroscopic tissue adherence was visible following 31 of the ablative procedures, all with radiofrequency ablation. Four applications were performed percutaneously and 27 during an open procedure. Morphologically intact tumour cells could be identified in 8 patients (20%), and viable tumour cells in 5 patients (12.5%). Morphologically intact tumour cells or viable tumour cells could only be demonstrated when track ablation was not performed. Conclusion: Viable tumour cells adherent to the needle applicators were found in an alarming 12.5% of patients after local ablation. We recommend track ablation not only after the procedure but also during any shifting and (re-)positioning to prevent shedding of viable tumour cells during or after ablation.

Re: Assessment of Viable Tumour Tissue Attached to Needle Applicators after Local Ablation of Liver Tumours

“…The authors commented that the finding in our earlier publication [2] where intact tumor cells were detected by simple HE examinations on tissue extracted on the RITA Starburst XL electrode after ablation of liver malignancies is remarkable. This finding was not in accordance with their findings where viable tumor was only found on the Leveen Radiotherapeutics device [1] . In order to improve the limitations of morphologic stains alone in our initial study [2] , we performed evaluation of fixed specimens with proliferation marker Ki67 [3,4] and apoptosis marker caspase 3 [5] .…”

“…We have certain questions regarding the methodology of Snoeren et al [1] : (1) Is it possible that any cells reacting to the G6PD were normal viable hepatocytes and not tumor? (2) Macroscopic tissue adherent on RITA electrodes was seen in 87.5% cases.…”

“…(4) The inability to resect with a clear, tumor-free margin, and multifocal and extrahepatic disease were indications for ablation. Was the ratio of patients with these factors similar between the Dear Sir, We have read with great interest the paper by Snoeren et al, entitled 'Assessment of viable tumour tissue attached to needle applicators after local ablation of liver tumours' [1] . The authors commented that the finding in our earlier publication [2] where intact tumor cells were detected by simple HE examinations on tissue extracted on the RITA Starburst XL electrode after ablation of liver malignancies is remarkable.…”

Evaluation of YO-PRO-1 as an early marker of apoptosis following radiofrequency ablation of colon cancer liver metastases

“…In addition, very little is known about the histopathologic and intracellular changes in the surrounding liver tissue. Previous studies have examined tissues adherent to the electrode used for ablation (Sofocleous et al 2004), and processed them for Hematoxylin and Eosin (H&E) and other cell viability and proliferation assays (Snoeren et al 2009(Snoeren et al , 2011Sofocleous et al 2008Sofocleous et al , 2012. The techniques described require tissue fixation and processing and/ or staining that cannot be completed in an expedited fashion.…”

“…Based on these findings, we postulated that YP1 could also be used in human liver tissues obtained after RFA, and would thus allow an early assessment of apoptosis leading to cellular death. In the current study, we obtained tissues adherent to the electrodes used in the RFA procedure, as previously described (Snoeren et al 2009(Snoeren et al , 2011Sofocleous et al 2004Sofocleous et al , 2008Sofocleous et al , 2011. Further, we performed needle biopsies from central and marginal regions of the ablation zone in an effort to collect additional tumor and surrounding liver tissue for analysis and to permit us to include cases with no tissues adherent to the electrode.…”