Role of FDG PET-CT in prognostication of Hepatocellular carcinoma patients undergoing Transarterial Radioembolisation

Objectives Transarterial Radioembolisation (TARE) using ⁹⁰Y-microspheres is a promising treatment modality for inoperable Hepatocellular carcinoma (HCC) patients. The aim of this study was to evaluate the prognostic role of pre therapeutic ¹⁸F-FDG PET-CT scan in HCC patients undergoing TARE

Methods A retrospective analysis of 54 patients of inoperable HCC who underwent ¹⁸F FDG PET-CT as part of pre TARE work up from January 2010 to Aug 2014. The overall survival of the patients with FDG avid tumors was compared to those showing no FDG uptake, using Kaplan Meier method. The prognostic significance of other parameters- Child Pugh’s score, Barcelona Clinic Liver Cancer (BCLC) stage, Serum Alfa-fetoprotein (AFP), presence of Ascites, presence of Portal vein &/or Inferior Vena Cava tumor thrombosis , viral markers and Age was evaluated by Univariate analysis.

Results The median follow up was 11.10 months. 41 patients died. 4 patients were lost to follow -up and were excluded. Out of 50 patients, 30 patients showed FDG avid tumors while in 20 patients the tumor was non FDG avid. Median overall survival in FDG avid subgroup was 10.71 months (95 % CI 8.85-12.56); while in non FDG avid subgroup was 20.46 months (95% CI 12.19-28.73). By Univariate analysis, FDG avidity of the tumor was the only statistically significant prognostic factor (P=0.030). The range of SUV max values in FDG avid subgroup was 4.00- 38.0 gm/dl with median SUV max - 10 gm/dl. By ROC curve analysis, the cut off SUV max was 9.85 gm/dl. The median survival in patients with SUV max < 9.85 gm/dl was 18.95 months and with SUV max >9.85 gm/dl was 6.66 gm/dl which was statistically significant (P=0.009).

Conclusions FDG avidity in HCC is an important prognostic factor predicting overall survival in patients undergoing TARE. Patients with higher SUV max values have poor survival. ¹⁸F FDG PET/CT scan can have a valuable role in pre-TARE work up of HCC patients.