Capivasertib treatment associated with hypermetabolism of the spleen

Capivasertib has emerged as a promising treatment for advanced breast and prostate cancer. Here, we report two cases of metastatic breast cancer patients who developed splenic hypermetabolism on [18 F]-FDG PET/CT following treatment with capivasertib. To our knowledge, these are the first documented instances of this treatment-related phenomenon. Although the mechanism behind this side effect remains unclear, these cases highlight an important imaging phenomenon that radiologists should consider when interpreting [18 F]-FDG PET/CT scans in patients treated with capivasertib.