Prognostic impact of carbohydrate antigen 19-9 level at diagnosis in resected stage I-III pancreatic adenocarcinoma: A U.S. population study

Background: Pancreatic adenocarcinoma is a highly aggressive cancer, with surgical resection and systemic therapy offering the only hope for long-term survival. Carbohydrate antigen 19-9 (CA 19-9) has been used as a prognostic marker after resection; however, the relationship between survival and pre-treatment CA 19-9 level remains unclear. This study evaluates pre-treatment serum CA 19-9 level as a predictor for long-term survival. Methods: The U.S. National Cancer Data Base [2004-2012] was reviewed for patients with clinical stages I-III resected pancreatic adenocarcinoma with recorded pre-treatment CA 19-9 levels (U/mL). Kaplan Meier and Weibull survival analyses were performed. Results: Four thousand seven hundred and one patients were included: 12.6% received neoadjuvant therapy (NAT), 27.4% underwent surgery, and 60.1% underwent surgery and adjuvant therapy. Amongst those who underwent initial surgery, there was no association between CA 19-9 levels ≤00 (≤100, 101-300, 301-500, 501-800) with survival (stage I P=0.7592, stage II P=0.5088, stage III P=0.9037). Levels > 800 were associated with significantly worse survival in all stages (P≤0.0001, all). Amongst those who received NAT, levels > 800 were associated with worse survival in early (stage I P=0.0001), but not advanced stage disease (stage II P=0.1891, stage III P=0.9316). In multivariable analyses, levels > 800 demonstrated a 3.29 greater hazard of mortality with respect to patients with levels ≤100 (P < 0.0001). Conclusions: Pre-treatment CA 19-9 levels > 800 appear to be associated with advanced disease, and are negatively associated with long-term survival. However, levels ≤800 had no significant association with survival. Although this study suggests an association, further study is needed to evaluate whether patients with CA 19-9 levels > 800 benefit from NAT.