Background: Data from retrospective studies shows that serum CA 19-9 antigen level may correlate with resectability and overall survival in patients with pancreatic cancer (PC). Methods: Patients were enrolled as part of an ongoing protocol designed to prospectively evaluate different diagnostic modalities for the diagnosis and staging of PC. 42 of 65 patients suspected of having PC underwent EUS (n=14) and contrast CT (n=42) followed by exploratory laparotomy if no clear cut indication of unresectability was evident. EUS and CT criteria of unresectability included evidence of vascular involvement (proximity, loss of interface, irregular vessel wall), extra-pancreatic invasion and distant metastasis. Surgical resectability was defined as the ability to remove the tumor en bloc. Serum CA 19-9 antigen was drawn preoperatively in all 42 patients (range 1- 13 days before surgery, cutoff > 37 U/ml) and measured by a reference lab using a commercially available radioimmunoassay kit. The aim of this analysis was to determine if a specific level of CA 19-9 correlates with unresectability as predicted by imaging studies (EUS and CT) and confirmed by laparotomy. Results: The mean age was 59 (range 39-81); M:F 22:20. Overall, 33 patients were found unresectable during exploratory laparotomy. 29/33 patients had a CA 19-9 level > 1,000 U/ml (87 %), mean 2300 ±806 U/ml and 540±355, unresectable vs. resectable patients (p value <0.05). The following table summarizes rates of (+) and (-) results for unresectability, using a cutoff value of CA 19-9 > 1000 U/ml as an unresectability criterion. Test characteristic CA 19-9 > 1000 U/ml EUS CT True Positive 29 8 26 True Negative 8 5 7 False Positive 1 0 2 False Negative 4 1 7 Sensitivity 29/33 87% 8/9 88% 26/33 79% Specificity 8/9 88% 5/5 100% 7/9 77% Accuracy 37/42 88% 13/14 93% 33/42 79% Conclusions: The sensitivity, specificity and accuracy of a CA 19-9 level > 1000 U/ml for unresectability is similar to EUS and abdominal CT. This tumor marker could be used as an additional tool to other imaging criteria to predict unresectability but these results need to be confirmed in a larger series of patients.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging