Decrease in total lesion glycolysis and survival after yttrium-90-radioembolization in poorly differentiated hepatocellular carcinoma with portal vein tumour thrombosis

Purpose This study aims to evaluate the prognostic role of the decrease in total lesion glycolysis (TLG) assessed by fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET-computed tomography (CT) 1 month after yttrium-90-radioembolization (90 Y-RE) in patients affected by hepatocellular carcinoma (HCC) with portal vein tumour thrombosis (PVTT). Patients and methods Twenty-one patients with histologically proven poorly differentiated HCC and evidence of PVTT at the enhanced multislice CT underwent 90 Y-RE. All patients underwent an 18 F-FDG PET-CT scan at baseline and 1 month after the loco-regional therapy. The variation in TLG (ΔTLG) between the two studies was calculated. Patients were divided in two groups (group 1: 1 month ΔTLG >50%, group 2: ΔTLG <50%). Statistical analysis was carried out to assess the prognostic role of TLG in overall survival (OS). Results On the 21 patients enrolled, all presented a decrease in TLG after the administration of 90 Y-microspheres. The OS was 11.5±1.2 months. Nine out of 21 (42.9%) patients showed ΔTLG more than 50% with a mean OS of 16.8±1.3 months, whereas the remaining 12 (57.1%) patients had ΔTLG less than 50% with a mean OS of 7.5±0.5 months. Statistical analysis showed ΔTLG to be a significant (P<0.001) predictor of survival. None of the other examined variables including age, Child-Pugh classification, previously performed therapies, the presence of extrahepatic metastases, α-fetoprotein and bilirubin levels had a significant prognostic impact on patients' outcome. Conclusion Decrease in TLG measured by 18 F-FDG PET-CT is correlated with a trend towards a longer median survival in patients affected by HCC and PVTT who have undergone 90 Y-RE.