MYOCARDIAL FDG UPTAKE VARIATION AND ITS RELATIONSHIP WITH SURVIVAL DURING IMMUNOTHERAPY

Background: The rise of Immune Checkpoint Inhibitors (ICI) as a cancer treatment has been followed by the increase of cardiotoxicity events reports. Retrospective studies with anthracycline revealed a relationship between increased myocardial 18F-FDG uptake (MGU) and a slight drop in Left Ventricular Ejection Fraction values, suggesting that this may be a useful tool for early detection of cardiotoxicity. Our study is intended to evaluate the prognostic impact of the variation in MGU in advanced lung cancer undergoing treatment with ICI. Methods: This is a unicentric, retrospective study, that evaluated lung cancer patients treated with ICI from 2016 to 2021 and submitted to at least two positron emission tomography (PET-CT). The primary objective was to evaluate the MGU variation during ICI treatment (∆SUV) and its impact on survival outcomes. Results: 59 patients fulfilled all inclusion criteria. 51% received Immunotherapy in combination with chemotherapy and 49% received only immunotherapy. Global median ∆SUV was +0.05; Among patients in the disease control group, the median ∆SUV was +0.48, while the median ∆SUV of the disease progression group was -0.66. Considering patients with positive myocardial ∆SUV versus negative ∆SUV, there was a median increase of progression-free survival (PFS) of 161 days in favour of the positive myocardial ∆SUV group (p = 0.066) and increase of 281 days on Overal Survival (p = 0.256). There was an increase of 759 days in the OS of diabetic patients (p=0.023), and better results in metformin users (p=0.015), in addition to an increase of 285 days in favor of beta-blocker (BB) users (p=0,886). The trend data found indicate that BB and/or metformin could perhaps have a supporting role in the treatment of ICI. These findings correlate with recent evidence showing an increase in MGU after BB use and that BB may function as immunomodulatory agents improving immunotherapy results. Conclusions: The increase in MGU was associated with better outcomes, suggesting that perhaps it could be studied as a predictor of treatment response, in addition to the trend of benefit also shown with the use of metformin and BB, which strengthens their possible synergistic effect in treatment. However, more robust studies are needed to better understand the MGU role on ICI treatment.