Background and Aims: Pancreatic ductal adenocarcinoma has one of the worst prognosis
of all malignancies. This investigated the relationship between the preoperative serum
carbohydrate antigen 19-9 and surgical resectability. Methods: A systematic search
was performed in three databases (MEDLINE, EMBASE, and Web of Science) to compare
the surgical resectability of pancreatic ductal adenocarcinoma in patients with high
and low preoperative serum carbohydrate antigen 19-9 values. The receiving operating
characteristic curves were constructed and the weighted mean differences for preoperative
serum carbohydrate antigen 19-9 levels of resectable and unresectable groups of patients
were calculated. The PROSPERO registration number is CRD42019132522. Results: Results
showed that there was a significant difference in resectability between the low and
high carbohydrate antigen 19-9 groups. Six out of the eight studies utilised receiver
operating characteristic curves in order to find the cut-off preoperative carbohydrate
antigen 19-9 levels marking unresectability. The overall result from the pooled area
under curve values from the receiver operating characteristic curves was 0.794 (CI:
0.694-0.893), showing that the preoperative carbohydrate antigen 19-9 level is a "fair"
marker of resectability. The result of the pooled weighted mean differences was 964
U/ml (p < 0.001) showing that there is a significant carbohydrate antigen 19-9 difference
between the resectable and unresectable groups. Based on the results of the I-squared
test, the result was 87.4%, accounting for "considerable" heterogeneity within the
population. Conclusion: Carbohydrate antigen 19-9 is not a reliable marker of unresectability,
it should not be used on its own in surgical decision-making.
