Subclinical Vascular Inflammation in Patients Receiving Pembrolizumab Detected by 18F-FDG PET/CT

Background: Immune checkpoint inhibitors have revolutionized the treatment of many tumors. Despite good clinical outcomes, unique immune-related adverse complications can occur with their use. Cardiac-related adverse events have been reported with pembrolizumab. However, data on the current trends of vascular inflammation in patients who received pembrolizumab are lacking. Patient and Methods: We chose the target-to-background ratio of the ascending aorta (TBR AA ), derived from 18 F-FDG tracer PET to capture changes in subclinical vascular inflammation after pembrolizumab administration. Our sample was drawn from a consecutive cohort of patients, with 70 out of 786 patients in our population pool meeting the inclusion criteria. Results: The median TBR AA before and after pembrolizumab therapy was 1.30 (interquartile range: 1.20–1.41) and 1.36 (interquartile range: 1.25–1.49), respectively. The difference between pre to post-pembrolizumab administration was statistically significant, with a P value of 0.02. When adjusted for risk factors and number of doses to predict change from pre to post-pembrolizumab administration TBRs, none of the variables was associated with the changes seen in TBR post-pembrolizumab therapy. Conclusion: Our analysis showed that there is a statistically significant median increase in the TBR AA after pembrolizumab administration, revealing evidence of a modest increase in vascular inflammation in patients receiving the drug.