Differential impact of incrementally elevated CA 19-9 levels on prognosis of resected pancreatic ductal adenocarcinoma.

ABSTRACT

BACKGROUND: CA 19-9 is an extremely useful biomarker for pancreatic ductal adenocarcinomas (PDACs). However, the optimal cut-off and prognostic significance at higher cut-offs are yet to be determined. METHODS: Retrospective analysis included patients with PDAC who underwent curative resection from January 2010 to May 2020 at Tata Memorial Centre, Mumbai. The pretherapy CA 19-9 was dichotomized using various cut-off levels and analysed. RESULTS: In 244 included patients, the median overall survival (OS) for those with CA19-9 level (IU/ml) < or >78, 200, 500, 1000, and 2000 was 27, 24, 23, 22, 21 months versus 18, 16, 15, 14, 13 months; respectively, and was statistically significant (p-value- 0.002, 0.001, 0.002, 0.002 and 0.004, respectively). The number of recurrences and mortality had significant correlation with CA 19-9 cut-offs. On multivariate analysis, adjuvant treatment completion (p-0.004) and decreasing or stable CA19-9 after Neoadjuvant therapy (NAT) (p- 0.031) were associated with improved OS. CONCLUSION: The prognostic significance of CA 19-9 was observed at all the cut-off levels examined, beyond mere elevated value as per the standard cut-off level. In patients with high CA19-9 level, surgery should be offered if technically and conditionally feasible, only when a response in CA19-9 level to NAT is achieved.