The following differences were not statistically significant: patients’ age; CEA tumor marker levels; primary GTV; BED10 of irradiation for the primary pancreatic tumor; total target GTV, including metastatic lesions; number of metastatic lesions; number of organs affected by metastasis; organs displaying metastasis (liver/other); with or without peritoneal dissemination; with or without ascites; with or without pre-PBT/concurrent chemotherapy; and duration from stage IV diagnosis to the initiation of PBT. Here, CEACAM5 is linked to pancreatic neoplasm.