Elevated serum CEA is associated with liver metastasis and distinctive circulating tumor DNA alterations in patients with castration‐resistant prostate cancer

Background Elevated serum carcinoembryonic antigen (CEA) is used to identify “treatment emergent” forms of castration‐resistant prostate cancer (CRPC) such as aggressive variant prostate cancer (AVPC). However, its individual utility as a prognostic marker and the genetic alterations associated with its expression have not been extensively studied in CRPC. Methods This study retrospectively analyzed clinical outcomes and circulating tumor DNA profiles in 163 patients with CRPC and elevated or normal serum CEA. These same patients were then classified as AVPC or non‐AVPC and compared to determine the uniqueness of CEA‐associated gene alterations. Results Patients with elevated CEA demonstrated higher rates of liver metastasis (37.5% vs. 19.1%, p = 0.02) and decreased median overall survival from CRPC diagnosis (28.7 vs. 73.2 mo, p