Background: Patient triage in anatomically resectable, early-stage pancreatic ductal adenocarcinoma (PDAC) with elevated carbohydrate antigen 19-9 (CA 19-9) remains unclear. We hypothesized that any CA 19-9 elevation indicates biologically borderline resectability. Study Design: The National Cancer Data Base (NCDB 2010 to 2012) was reviewed for PDAC patients with reported CA 19-9. Nonsecretors were analyzed separately. Early-stage (I/II) patients were stratified by CA 19-9 above or below normal (37 U/mL). Unadjusted Kaplan-Meier and adjusted Cox proportional hazards survival modeling were performed. Results: Of 113,145 patients, only 28,074 (24.8%) had CA 19-9 measured and reported, and this proportion was stage independent. Among early-stage patients (n = 10,806), there were 957 (8.8%) nonsecretors, 2,708 (25.1%) with normal levels, and 7,141 (66.1%) with elevated levels. Demographics and perioperative outcomes were similar between these groups. Survival was worse in all stages in patients with CA 19-9 elevation. Nonsecretors had survival similar to that of patients with normal levels. Early-stage patients with elevated CA 19-9 had decreased survival at 1, 2, and 3 years (56% vs 68%, 30% vs 42%, 15% vs 25%, all p <0.001) relative to patients with normal levels. Adjusted modeling confirmed this finding (hazard ratio [HR] 1.26, p <0.001). Repeat modeling in the neoadjuvant cohort demonstrated this to be the only treatment sequence to completely abrogate increased mortality due to CA 19-9 elevation (p = 0.11). Conclusions: The minority of PDAC patients have CA 19-9 measured and reported in NCDB. The CA 19-9 nonsecretors and normal-level patients achieve equivalent survival. Elevation of CA 19-9 is associated with decreased stage-specific survival, with the greatest difference in early stages. Neoadjuvant systemic therapy followed by curative intent surgery best mitigates the increased mortality hazard. Patients with PDAC who have elevated CA 19-9 levels at diagnosis are biologically borderline resectable regardless of anatomic resectability, and neoadjuvant systemic therapy is suggested.
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