Pretreatment Positron Emission Tomography with 18F-Fluorodeoxyglucose May Be a Useful New Predictor of Overall Prognosis Following Lenvatinib Treatment

Abstract

Background and Aim: The aim of this study was to identify the utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) as a predictor of overall prognosis in patients with hepatocellular carcinoma treated with lenvatinib. Methods: Forty-eight consecutive patients who received lenvatinib treatment were reviewed. The oncological aggressiveness of tumors estimated using 18F-FDG-PET/CT was investigated by the analysis of progression-free survival (PFS), post-progression survival (PPS), and overall survival (OS). Multivariate analysis was used to identify potential confounders for OS during lenvatinib therapy. Results: Using the Modified Response Evaluation Criteria in Solid Tumors, a tumor-to-normal liver ratio (TLR) ≥2, indicating higher oncological aggressiveness in HCCs, was associated with a better objective response to lenvatinib than a TLR <2 (78 vs. 62%), resulting in a similar PFS (p = 0.751). Because of a significantly worse PPS, OS with a TLR ≥2 was poor compared to a TLR < 2 (p = 0.012). Multivariate analysis confirmed that a TLR ≥ 2 was associated with poor OS (hazard ratio, 2.709; 95% CI, 1.140–6.436; p = 0.024). Analysis of 24 patients who received a repeat 18F-FDG-PET/CT showed that daily changes expressed as ΔTLR × 103/day over the treatment course tended to be different among the types of subsequent treatment. A R0 resection and lenvatinib-TACE sequential therapy provided good disease control (median, −4.593 and −0.024, respectively) compared with other treatments (median, 5.278) (p = 0.075). Conclusion: Lenvatinib has acceptable disease control regardless of estimated tumor differentiation. A high TLR (≥2) is a poor prognostic factor of OS following lenvatinib treatment, while ΔTLR × 103/day provides useful information of disease control status.