Embryologic tumor location combined with carbohydrate antigen 19-9 stratifies biological risk in resectable pancreatic head cancer.

BACKGROUND: For anatomically resectable pancreatic cancer, a "biological borderline resectable" concept based on carbohydrate antigen 19-9 (CA19-9) elevation or suspected nodal metastasis is proposed; however, preoperative nodal staging remains imprecise. We evaluated whether embryologic tumor location combined with CA19-9 can stratify biological risk of resectable pancreatic head cancer (RPHC). METHODS: We retrospectively analyzed 78 patients who underwent pancreaticoduodenectomy for RPHC between January 2010 and June 2024. Embryologic tumor location was determined from preoperative imaging and categorized as ventral or dorsal pancreas. The optimal pretreatment CA19-9 cutoff for overall survival was determined using maximally selected rank statistics. Associations between embryologic tumor location, CA19-9, and survival outcomes were examined, and predictors of recurrence were identified using Cox proportional hazards models. RESULTS: An optimal CA19-9 cutoff of 150 U/mL was identified. Dorsal tumors were associated with shorter recurrence-free survival (RFS) (p = 0.004) and overall survival (OS) (p = 0.048), while CA19-9 levels > 150 U/mL were associated with worse RFS (p = 0.015) and OS (p < 0.001). On multivariate analysis, dorsal location (hazard ratio [HR] 2.30, p = 0.035) and CA19-9 levels > 150 U/mL (HR 1.93, p = 0.024) remained independent predictors of recurrence, whereas clinical nodal status was not (HR 1.91, p = 0.149). A three-tier classification combining tumor location and CA19-9 stratified patients by RFS (p = 0.001) and OS (p < 0.001), with dorsal/high-CA19-9 tumors showing the poorest outcomes. CONCLUSIONS: Integrating embryologic tumor location with CA19-9 levels may refine risk stratification in RPHC and help guide treatment strategies.