Preoperative carbohydrate antigen 19-9 and standard uptake value of positron emission tomography-computed tomography as prognostic markers in patients with pancreatic ductal adenocarcinoma.

Background: Among various prognostic factors of pancreatic cancer, preoperative clinical information is obtained by imaging modality. This study aimed to evaluate clinical usefulness of preoperative carbohydrate antigen and preoperative standard uptake value in 18F-fluorodeoxyglucose positron emission tomography as predictive biological markers for resectable pancreatic ductal adenocarcinoma.

Methods: A total of 189 patients with PDAC who underwent preoperative PET-computed tomography were evaluated. Patients underwent neoadjuvant chemotherapy, and R2 resection was excluded. The correlation between SUVmax and clinicopathologic parameters was analyzed. The C-tree statistical method was used to estimate cutoff values of logCA19-9 and SUVmax for survival rate. A multivariate analysis was conducted to identify prognostic factors for overall survival.

Results: The median duration of OS was 26 months, and the 5-year survival rate was 22.4%. The optimal cutoff values for CA19-9 level was 150 U/mL and SUVmax was 5.5. When subjects were divided into three groups according to the combination of CA19-9 level and SUVmax from C-tree (high-risk group, CA19-9 > 150 U/mL and SUVmax > 5.5; intermediate-risk group, CA19-9 ≤ 150 U/mL and SUVmax > 5.5 or CA19-9 > 150 U/mL and SUVmax ≤ 5.5; and low-risk group, CA19-9 ≤ 150 U/mL and SUVmax ≤ 5.5), there was a significant 5YSR difference (5.6%, 24.3%, and 36.5%, P < .001). The multivariate analysis revealed high SUVmax, high preoperative CA19-9 level, venous invasion, and adjuvant chemotherapy were prognostic factors of OS.

Conclusions: CA19-9 and SUVmax are strong prognostic biological factors in resectable PDAC. Moreover, patients with high CA19-9 level and SUVmax are not indicated for upfront surgery.