11C-acetate and 18F-FDG dual tracer PET scan with contrast CT provide the most accurate histopathology prediction in HCC patients - a study of explant histopathology in the model of liver transplantation

Abstract

BACKGROUND: All of the liver transplantation criteria for HCC depend heavily on tumor size and numbers. However, the sensitivity of contrast CT scan and MRI ...

BACKGROUND: All of the liver transplantation criteria for HCC depend heavily on tumor size and numbers. However, the sensitivity of contrast CT scan and MRI is far from satisfactory. We investigated whether contrast computed tomography (CT) together with positron emission tomography (PET) using two tracers, 11C-acetate and 18F-FDG, provides a more accurate prediction of histopathological status by comparing directly to the liver explants. METHOD: Data of 44 HCC patients having the dual-tracer PET together with contrast CT before surgery between January 2004 and September 2011 were reviewed. Eleven patients underwent deceased donor liver transplantation and 33 patients underwent living donor liver transplantation. All patients had HCC proven by histopathological assessment. RESULTS of HCC staging in terms of the size and number yielded by contrast CT, 18F-FDG PET and dual-tracer PET with contrast CT were compared with histopathology after surgery. Results: A total 72 tumors were identified in these 44 patients. The median tumour number were 1 (range1-5) and the median size was 3.75cm (range 1-8cm) from the final pathology. The overall accurate prediction of final histopathology in terms of UCSF criteria by contrast CT scan alone was 21/44 (47.7%), by FDG alone was 13/44 (29.5%), by 11C acetate alone 32/44 (72.7%) and by overall combination of 3 assessment was 33/44 (75%) (p=0.000*) From the pathological examination, there were 4 tumors < 1cm, the sensitivity by contrast CT scan alone, by 18FDG alone, by 11C acetate alone and by overall combination of 3 assessment were 0%, 25%, 25%, and 25% respectively (p=0.746). There were 23 tumours range from 1- 2 cm, the sensitivity by contrast CT scan alone, by 18FDG alone, by 11C acetate alone and by overall combination of 3 assessment were 60.9%, 17.4%, 73.9%, and 78.3% respectively (p=0.000*). There were 45 tumours > 2cm, the sensitivity by contrast CT scan alone, by 18FDG alone, by 11C acetate alone and by overall combination of 3 assessment were 71.1%, 40%, 86.7%, and 91.1% respectively (p=0.000*) CONCLUSION: For lesions > 1 cm, dual-tracer PET together with contrast CT provided the most accurate prediction of explants histopathology in terms of tumor size and number for patients undergoing liver transplantation for HCC. Its implementation in liver transplant work-up is recommended.