Myocardial FDG uptake variation and its relationship with survival during immunotherapy.

Abstract

e14604 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 (LVEF) 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 2020 and submitted to at least two positron emission tomography (PET-CT). The primary objective was to evaluate the MGU variation during ICI treatment (ΔSUV) and its impact on survival outcomes. Numerical variables are described using a median and interquartile range. Categorical variables are described using absolute and relative frequencies. Mann-Whitney test was applied to compare the median between groups. progression-free survival and overall survival were calculated using the Kaplan-Meier method and the Log Rank test was used to compare survival curves. Alpha level = 0.05. Results: 43 patients fulfilled all inclusion criteria. 51% received Immunotherapy plus chemotherapy and 49% received only immunotherapy. Global median ΔSUV was +0.14; among patients in the disease control group, the median ΔSUV was +0.3, while the median ΔSUV of the disease progression group was -0.47. Considering patients with positive myocardial ΔSUV versus negative ΔSUV, there was a median increase of progression-free survival (PFS) of 112 days in favour of the positive myocardial ΔSUV group (p = 0.087). The overall survival (OS) of patients that used beta-blockers(BB) was higher than those who did not, with an increase of 575 days on median OS (p = 0.159). The increase in the PFS median by 112 days on those patients who presented a positive ΔSUV may suggest that better treatment outcomes are related to the rise of myocardial SUV, although the sample size was not sufficient to reach statistical significance. Another important association, albeit not statistically significant, was the growth of PFS mean by 575 days with the usage of BB, such growth was not evidenced on the patients which used ACE inhibitors or ARBs; indicating that BB could have a supporting role on ICI treatment. Those findings correlate to recent evidence that shows an increase in MGU after BB usage and that BB may work as immune-modulating agents improving ICI therapies. Conclusions: The increase in MGU was associated with better outcomes, suggesting that it could be studied as a predictor of treatment response, in addition to the benefit also shown with the use of BB, which strengthens their possible synergistic effect in treatment. However, more robust studies are needed to better understand the MGU role on ICI treatment.