Objective To evaluate the prognosis of patients with resectable pancreatic ductal adenocarcinoma (PDAC) treated by gemcitabine and nab-paclitaxel (AG) or AG combined with pro-grammed death-1 (PD-1) inhibitor regimen and application value of the Cleveland Clinic Foundation (CCF) risk score.

Methods The retrospective cohort study was conducted. The clinicopathological data of 151 PDAC patients who were treated by AG regimen or AG combined with PD-1 inhibitor regimen in Zhejiang Cancer Hospital from January 2013 to March 2024 were collected. There were 84 males and 67 females, aged (64±9)years. Observation indicators: (1) comparison of clinical characteristics among resectable PDAC patients with different CCF risk score; (2) analysis of influencing factors for overall survival time of resectable PDAC patients; (3) survival of resectable PDAC patients. Comparison of measurement data with skewed distribution between groups was conducted using the Mann-Whitney U test. Comparison of count data between groups was conducted using the chi-square test. Comparison of ordinal data between groups was conducted using the rank sum test. Univariate and multivariate analyses were conducted using the Cox regression model. Kaplan-Meier method was used to calculate survival rate and plot survival curve, and Log-rank test was used for survival analysis.

Results (1) Comparison of clinical characteristics among resectable PDAC patients with different CCF risk score. Based on CCF risk score, 102 of 151 patients were classified as low risk and 49 cases were classified as intermediate-to-high risk. There were signi-ficant differences in sex, age, smoking status, alcohol consumption, hypertension, and diabetes between the two categories (P<0.05). (2) Analysis of influencing factors for overall survival time of resectable PDAC patients. Results of multivariate analysis showed that the treatment regimen was an indepen-dent influencing factor for overall survival time of resectable PDAC patients (hazard ratio=1.976, 95% confidence interval as 1.065‒3.666, P<0.05). (3) Survival of resectable PDAC patients. The follow-up time of 151 patients was 21.8(18.7,24.2)months, and the median overall survival time was 23.3(19.0,32.4)months. The follow-up time was 22.1(18.9,30.7)months of patients treated by AG regimen and 11.2(8.1,23.3)months of patients treated by AG combined with PD-1 inhibitor regimen, respectively. The median overall survival time of the two types of patients was 24.4(17.2,31.7)months and 16.9(8.9,24.9)months. The 1-year overall survival rates were 79.1% and 60.0%, and the 2-year overall survival rates were 53.4% and 28.5%, respectively. There was a significant difference in the overall survival between the two types of patients (hazard ratio=1.913, 95% confidence interval as 1.041‒3.516, P<0.05). Of the intermediate-to-high risk patients, the follow-up time was 18.5(8.8,28.1)months of 37 patients treated by AG regimen and 8.1(7.3,9.0)months of 12 patients treated by AG combined with PD-1 inhibitor regimen. The median overall survival time of the two types of patients was 32.4(15.7,49.0)months and 8.9(5.7,12.1)months, respectively. The 1-year overall survival rates were 82.7% and 31.3%, and the 2-year overall survival rates were 66.5% and 0, respectively. There was a significant difference in the overall survival between the two types of patients (hazard ratio=5.402, 95% confidence interval as 1.811‒16.118, P<0.05).

Conclusions The treatment regimen is an independent influencing factor for overall survival in patients with resectable PDAC. Compared with the AG combined with PD-1 inhibitor regimen, AG regimen is associated with good survival of patients with resectable PDAC. For patients classified as intermediate-to-high risk based on the CCF risk score, AG regimen is assiociated with a better overall survival compared to AG combined with PD-1 inhibitor regimen.