Diagnostic performance of the FDG-PET/CT in patients with resected mucinous colorectal liver metastases

Background: and purpose: FDG-PET/CT has gained acceptance for tumours staging. Few and conflicting data exist on the sensitivity of FDG-PET/CT in identifying colorectal mucinous liver metastases (mucCRLM). The aim of this study was to evaluate the diagnostic performance of the FDG-PET/CT in patients with mucCRLM who underwent liver surgery. Methods: All patients affected by mucCRLM scheduled for liver resection who had undergone preoperative FDG-PET/CT between 2005 and 2018 were analyzed. Diagnostic performance of FDG-PET/CT was assessed in organ and lesion-based analysis. Results: 58 patients out of 131 (44.2%) affected by mucCRLM fulfilled the inclusion criteria. 118 mucCRLM were detected. FDG-PET/CT confirmed 71 (60.2%) CRLM in 51 patients. The sensitivity and specificity of FDG-PET/CT were 89.4% and 100% in the organ-based analysis and 60.7% and 100% in lesion-based analysis. Absence of micro-vascular invasion (100% vs. 23%, p < 0.001) and median percentage of viable tumour cells were associated with FDGPET/CT false negative (15% vs. 60%, p = 0.007). At ROC analysis viable tumour cells percentage >25% was associated with low risk of false negative (AUC 0.848; p = 0.006). Conclusions: FDG-PET/CT had a significant rate of false negative results in patients with mucinous colorectal liver metastases. Negative FDG-PET/CT in patients with low percentage of viable tumour cells after chemotherapy should be considered with caution. (C) 2020 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study evaluated the diagnostic performance of FDG-PET/CT in patients with mucinous colorectal liver metastases, showing sensitivity and specificity in both organ and lesion-based analysis. The research indicated that a low percentage of viable tumor cells may result in false-negative FDG-PET/CT findings.