MDPI AG Acta Medica Okayama 2072-6694 17 22 2025 Prognosis Prediction Model After Upfront Surgery for Resectable Pancreatic Ductal Adenocarcinoma: A Multicenter Study (OS-HBP-2) 3694 EN Kosei Takagi Department of Gastroenterological Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Ryuichi Yoshida Department of Gastroenterological Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Kazuya Yasui Department of Gastroenterological Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masayoshi Hioki Department of Surgery, Fukuyama City Hospital Takehiro Okabayashi Department of Surgery, Kochi Health Sciences Center Toru Kojima Department of Surgery, Okayama Saiseikai General Hospital Yoshikatsu Endo Department of Surgery, Himeji Red Cross Hospital Daisuke Nobuoka Department of Surgery, Fukuyama City Hospital Kenta Sui Department of Surgery, Kagawa Prefectural Hospital Masaru Inagaki Department of Surgery, National Hospital Organization Fukuyama Medical Center Susumu Shinoura Department of Surgery, Tsuyama Chuo Hospital Masashi Kimura Department of Surgery, Matsuyama Shimin Hospital Tatsuo Matsuda Department of Surgery, Tenwakai Matsuda Hospital Hideki Aoki Department of Surgery, National Hospital Organization Iwakuni Clinical Center Toshiyoshi Fujiwara Department of Gastroenterological Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Background/Objectives: Upfront surgery (UFS) remains the standard treatment for patients with resectable pancreatic ductal adenocarcinoma (PDAC). We aimed to investigate the prognostic factors for survival after UFS in patients with resectable PDAC and to develop a prognostic prediction model. Methods: This multicenter, retrospective study included 603 patients who underwent UFS for resectable PDAC between January 2013 and December 2017. Univariate and multivariate analyses were performed to identify prognostic factors for overall survival (OS). We constructed a prognostic prediction model for OS after UFS. An internal validation was performed to evaluate the discriminative performance of the model. Results: The 1-, 3-, and 5-year OS rates were 83.7%, 48.2%, and 37.5%, respectively. The Cox proportional hazards model showed that tumor size > 2 cm (hazard ratio [HR] 1.50, p = 0.001); tumor contact with the portal and superior mesenteric veins of ≤180�� (HR 1.47, p = 0.003); carbohydrate antigen 19-9 levels of 40 to 500 U/mL (HR 1.59, p = 0.002) and ≥500 U/mL (HR 2.16, p < 0.001); and a modified Glasgow Prognostic Score of two (HR 1.56, p = 0.038) were predictors associated with OS. The prognostic prediction model for 5-year OS demonstrated an area under the curve of 0.68. The calibration plots indicate a concordance index of 0.63. Conclusions: We identified the preoperative prognostic factors for OS and developed a prognostic prediction model to estimate OS in patients undergoing UFS for resectable PDAC. Our model may be useful and internally validated for predicting OS. No potential conflict of interest relevant to this article was reported.