Immuno-Fluorescent Assessment of Ablated Colorectal Liver Metastases: The Frozen Section of Image-Guided Tumor Ablation?

Abstract Purpose To validate an immuno-fluorescent assay (IFA) detecting residual viable tumor as intraprocedural thermal ablation (TA) zone assessment and demonstrate its prognostic value for local tumor progression after colorectal liver metastases (CLM) TA. Materials and Methods This prospective, IRB-approved study included 99 patients with 155 CLMs ablated between November 2009 and January 2019. Tissue samples from the ablation zone (AZ) center and minimal margin underwent immunofluorescent microscopic examination interrogating cellular morphology and mitochondrial viability (IFA) within 30 minutes after ablation. The same tissue samples were subsequently evaluated with standard morphological and immunohistochemical (IHC) methods. Sensitivity, specificity, and overall accuracy of IFA versus standard morphological and IHC examination were calculated. Local tumor progression (LTP)-free survival rates were evaluated for 12-month follow-up period. Results Of the 311 tissue samples stained, 304 (98%) were deemed evaluable. 27% (81/304) of specimens were considered positive for the presence of viable tumor. The accuracy of IFA was 94% (286/304). Sensitivity and specificity were 100% (63/63) and 93% (223/241), respectively. The 18 false-positive IFA assessments corresponded to samples that included viable cholangiocytes. The 12-month LTP-free survival was 59% vs 78% for IFA positive vs negative for viable tumor AZs, respectively (P Conclusion IFA assessment of the AZ can be completed intra-procedurally and serve as a valid real-time biomarker of complete tumor eradication or detect residual viable tumor after TA. This method could improve tumor control by TA.