James Franklin MA, MBBS, Presenter: Nothing to Disclose

Jean SZ Lee MRCP, MBBChir, Abstract Co-Author: Nothing to Disclose

Charles Dearman BA, Abstract Co-Author: Nothing to Disclose

Daniel Yiu Fai Chung MBBS, FRCR, Abstract Co-Author: Nothing to Disclose

Ewan Mark Anderson MBBCh, Abstract Co-Author: Nothing to Disclose

Fergus Vincent Gleeson MBBS, Abstract Co-Author: Alliance Medical Ltd Consultant

Percutaneous ablation has a role in the local treatment of colorectal liver metastases. Patients are typically selected for therapy based on technical, rather than biological, considerations. Pre-treatment techniques to allow improved patient selection for local therapy would be of clinical value. The aim of this study was to assess whether quantitative [18F]-FDG-PET/CT (PET/CT) was associated with patterns of disease relapse at 1 year.

This was a retrospective cohort study of 24 patients with solitary colorectal liver metastases, who underwent percutaneous ablation. All patients had a PET/CT scan prior to treatment. The presence of intra- or extrahepatic distant metastatic relapse at 1 year was determined by contrast-enhanced CT, and MRI or PET/CT where available. Patients with metastatic relapse were classified into oligometastatic or polymetastatic patterns of relapse; oligometastatic disease was defined as limited relapse (≤3 metastases), which remained amenable to local treatment. The PET/CT parameters SUVmax, SUVpeak, metabolic tumour volume (MTV) and tumour glycolytic volume (TGV) were derived using commercially available software (Hermes Medical Solutions, AB, Stockholm). The association of these parameters with patterns of subsequent metastatic relapse was tested using standard statistical techniques.  

The 24 patients were categorized as follows: 9 polymetastatic relapse, 4 oligometastatic relapse, 11 no relapse. All patients with an SUVmax > 13 had polymetastatic relapse within one year. There was a significant difference of SUVmax (7.47 vs 14.15, p=0.002) and TGV (79.5 vs 664.0, p=0.016) between those with polymetastatic relapse compared with oligometastatic or no relapse. The AUC for the ROC curve for SUVmax to predict polymetastatic compared with oligometastatic or no relapse at 12 months was 0.875 (Figure 1).  

Baseline PET/CT can provide prognostic information for patients undergoing percutaneous ablation for solitary colorectal liver metastases, which may allow improved patient selection for local therapy. This may be because FDG-uptake reflects underlying differences in tumour biology.

Selection for percutaneous ablation of colorectal liver metastases is based largely on technical, rather than biological, considerations. PET/CT can provide prognostic information, which may allow improved patient selection for local therapy.

Franklin, J, Lee, J, Dearman, C, Chung, D, Anderson, E, Gleeson, F, Pre-treatment FDG-PET/CT Predicts Distant Relapse Following Percutaneous Ablation for Colorectal Liver Metastases.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14012906.html