Clinical usefulness of dual-tracer PET/CT scan in treatment planning for hepatocellular carcinoma (HCC)

Abstract

Background Hepatocellular carcinoma (HCC) is one of the most common cancers in Asia due to the high prevalence of chronic viral hepatitis with incidence exceeding 30 cases/100,000 people per year. HCC is the forth most common cancer in Hong Kong and third most common cause of cancer morality. Therefore, prompt diagnosis is essential. HCC diagnosed gradually shifted radiologically with CT and MRI remains the mainstay of radiological modality. Positron Emission Tomography/ Computer tomography (PET/CT) is a new imaging technique with surge in research on this aspect. Dispite its high sensitivity and specificity, the cost-effectiveness of the scan regarding HCC work‐up remains unclear.

Methodology A retrospective review was done for patient who was referred for HCC work up at the Department of Surgery, Queen Mary Hospital, The University of Hong Kong, between December 2012 and September 2015. Patients with pre-assessment treatment, pre‐transplant work‐up; and Mono‐tracer PET/CT or patients without triphasic CT or MRI prior to Dual‐tracer PET will also be excluded from the study.

Results After exclusion, 152 patients were included in the study. Sensitivity and Specificity in detecting HCC is 95% and 100% respectively. PET/CT detected extrahepatic metastasis in 17 patients and only 12 patients changed management (8%) and were not cost-effective. Multivariable showed AFP≥400 (OR 4.3, (1.41 – 13.15), p=0.011) and bilobar involvement (OR 3.94, (1.24 - 12.52), p=0.014) are statistically significant as prognostic factors for detecting metastasis with high Negative Predictive value of 96%. After taking the multivariable into consideration for deciding the use of PET/CT, it is deemed cost‐effective.

Conculsion AFP≥400 and bilobar involvement associated with 4.3‐fold and 3.94‐fold increase risk of extrahepatic HCC metastasis respectively and has a high negative predictive value of 96%. PET/CT is an important staging investigation and decision on PET/CT after considering AFP and bilobar involvement significantly improves patient selection and its cost-effectiveness.