Abstract 1145P
Background
Uveal melanoma (UM) has 50% chance of relapse after local treatment. Metastatic UM (MUM) mainly affects liver. MUM is fatal and to date no systemic treatment has improved survival. We aimed to explore liver metastases (M1) metabolic activity in MUM as a potential biomarker for survival.
Methods
We retrospectively analyzed newly diagnosed pts with MUM in our centre between 2004-2019. Patients were included if presented liver M1 by a liver-directed imaging study (CT or MRI) and simultaneously underwent a PET/TC at diagnosis. Metabolic activity was measured by PET/TC SUVmax. Other relevant clinical prognostic variables were also analyzed.
Results
A total of 51 patients were included. Median age was 62 years, 41% male and 22% ECOG PS ≥ 1. LDH, ALP and GGT were elevated in 49%, 37% and 57% pts, respectively. 37% presented extrahepatic disease, 33% had ≥30mm liver M1 and 35% had <2-y M1 free interval. Median liver M1 SUVmax was 8.5 (3 – 42.2). Interestingly, same size lesions presented a wide range of metabolic activity. SUVmax for < 30mm lesions varied from 2.6 to 22.3, and from 4.4 to 42.2 for larger lesions suggesting metabolic heterogeneity. Median OS was 17.3m (95% CI: 10.6 - 23.9). Using SUVmax≥ 8.5 as a cutoff value showed an AUC=0.66 according to time-dependent survival ROC analysis. Patients with SUVmax ≥ 8.5 showed 9.4m (95% CI: 6.4-12.3) OS, whereas for SUVmax < 8.5 the OS was 38.4m (95% CI: 21.4-55.5)(P < 0.0001, HR=2.9). HR of SUVmax as a continuous variable was 1.068 (95% CI: 1.02-1.10; P = 0.001). That is, a 6.8% increase in hazard of death for each unit increase in SUVmax. For the multivariate analysis, 2 models were used. One with dichotomous SUVmax (≥ 8.5 vs <8.5) and other with continuous SUVmax. In both of them SUVmax remained significant. HR= 3.39 (95% CI: 1.56-7.35), P < 0.01 for SUVmax ≥ 8.5, and HR= 1.05 (95% CI: 1.01-1.03), p=0.001 for continuous SUVmax. Other clinical variables significant were < 2-y M1 free survival and diameter of largest M1.
Conclusions
Increased metabolic activity of liver metastases seems to be an independent predictor of survival. MUM is a heterogeneous disease and metabolic activity probably reflect a different intrinsic behaviour.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.