Prognostic significance of pretreatment 18F-FDG PET/CT in hepatocellular carcinoma: A systematic review and meta-analysis

Background & Aims 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) is not routinely recommended for hepatocellular carcinoma (HCC). Its prognostic role in patients with HCC remains unclear. This meta-analysis aims to evaluate the prognostic significance of 18 F-FDG PET/CT in HCC. Methods A systematic literature search was conducted until August 2024 to identify studies evaluating the prognostic value of 18 F-FDG PET/CT in patients with HCC. Studies were included if they reported an association between pre-treatment PET/CT and clinical outcomes, including overall survival (OS), recurrence-free survival (RFS), and progression-free survival (PFS). A random-effects model was employed with heterogeneity assessed using the I 2 statistic. Results We identified 59 relevant studies (6 prospective and 53 retrospective) including 8,585 patients. Pre-treatment 18 F-FDG PET/CT was positive in 30.8% of patients with HCC. Increased FDG activity was associated with poorer OS (HR 2.05, 95%CI:1.77–2.38, I 2 =71.6%), RFS (HR 3.18, 95%CI:2.08–4.86, I 2 =96.8%), and PFS (HR 1.64, 95%CI:1.36–1.98, I 2 =71.8%), respectively. FDG activity was significantly associated with OS for both curative (HR: 2.10, 95%CI:1.58–2.80, I 2 =62%) and non-curative (HR: 2.28, 95%CI:1.59–3.25, I 2 =75.3%) treatments. The prognostic significance of 18 F-FDG PET/CT remained consistent across various PET/CT parameters, including SUVmax, tumor-to-liver ratio, and visual assessment of PET/CT positivity, and curative/non-curative therapeutic modalities, all demonstrating that higher FDG uptake is associated with poorer clinical outcomes. Conclusions Pre-treatment 18 F-FDG PET/CT is positive in 30.8% of patients with HCC and is significantly associated with clinical outcomes in HCC patients. These findings support its prognostic relevance in HCC, while further studies may help refine its clinical role and standardize 18 F-FDG PET/CT-based risk stratification. PROSPERO ID CRD42025633333. Impact and implications Patients with high FDG tumor uptake have significantly poorer survival across various treatments. The potential role of 18 F-FDG PET-CT for patient selection and as a prognostic tool should be further investigated.