Pre-operative CA 19-9 as a predictor of recurrence and survival in resected pancreatic ductal adenocarcinoma

Pre-operative levels of CA 19-9 for pancreatic ductal adenocarcinoma (PDCA) have been extensively studied as a prognostic tool in recurrence and survival; however, contradictory evidence has prevented its role from being defined. 

We examined data from 287 patients diagnosed with PDCA between 2007-2016. From these patients, 117 had pre-operative CA 19-9 levels and only 90 were resected. A threshold of 37U/ml for serum levels of CA 19-9 were used to compare “normal-levels” and “elevated-levels”. Both groups were compared retrospectively. Post-operative complications using Clavien-Dindo classification, early tumour recurrence (within the first 6 months post-surgery) and survival were assessed as primary outcomes. Kaplan-Meier curves were used to visually present early recurrence and time to mortality; each curve was compared between CA 19-9 groups using the log-rank test. We created a Cox proportion-hazards model to estimate the association of elevated-levels of CA 19-9 with mortality, adjusting for total bilirubin and tumour-stage.

The median CA 19-9 for the normal-levels group was 12(3-19)U/mL and for the elevated-levels group was 118 (70-398)U/mL. The survival curve for early recurrence was not statistically significant between groups, p=0.4, however, elevated levels of CA 19-9 showed to have a negative impact on survival over  5-years, p=0.049, and a HR of 2.2, 95% CI 1.2-4.14, p=0.011. Post-operative complications between normal-levels and elevated-levels of CA 19-9 were 56.8% vs. 62.3% (p=0.86). Tumour stage differences between groups was not statistically significant (p=0.48) and levels of CA 19-9 were adjusted to levels of bilirubin. 

Our study showed that high levels of pre-operative CA 19-9 were not associated with early recurrence in PDCA, but were significantly associated with mortality. Future studies with greater sampling could support the creation of a composite model capable of predicting morbidity and mortality outcomes.

Pre-operative CA 19-9 as a Predictor of Recurrence and Survival in Resected Pancreatic Ductal Adenocarcinoma