Risk stratification of pancreatic ductal adenocarcinoma patients undergoing curative-intent surgery after neoadjuvant therapy.

Abstract

e16312 Background: To identify preoperative factors associated with survival in pancreatic ductal adenocarcinoma (PDAC) patients who underwent curative-intent surgery after neoadjuvant therapy (NAT) and develop risk stratification criteria. Methods: Consecutive PDAC patients who underwent post-NAT curative-intent surgeries between 2007 and 2020 at a high-volume center were retrospectively analyzed. Demographic, laboratory, surgical, and histopathologic variables were collected. Baseline, preoperative, and interval changes of CT findings proposed by the Society of Abdominal Radiology and the American Pancreatic Association were analyzed. Cox proportional hazard analyses were used to identify preoperative variables associated with survival since the time of diagnosis. We developed risk stratification criteria using the variables independently associated with survival, i.e., "post-NAT response criteria." We compared the discrimination performance of "post-NAT response criteria" with that of post-NAT pathological (yp) AJCC TNM staging system. Results: A total 145 PDAC patients who completed chemo- (n=47) or chemoradiation therapy (n=98) were included. Stable or increased tumor size on CT (hazard ratio, 2.58 [1.58, 4.21]; P < 0.001) and elevated preop. CA 19-9 level (1.98 [1.11, 3.55]; P = 0.021) were independent poor prognostic factors. The survival of the patient groups stratified by "post-NAT response criteria" which combined changes in tumor size and CA 19-9 showed significant difference (P < 0.001). Such stratification was comparable to ypTNM staging in discrimination performance (difference of C-index, 0.068 [-0.012, 0.142]). Conclusions: Decrease in tumor size and CA 19-9 normalization or staying normal until the time of surgery were independent favorable factors of survival. The combination of the two factors discriminated survival comparably to ypTNM staging.[Table: see text]