Tumor budding is an independent adverse prognostic factor of pancreatic ductal adenocarcinoma patients treated by resection after preoperative chemoradiotherapy.

OBJECTIVES: To examine the significance of tumor budding as a prognostic factor of resected pancreatic ductal adenocarcinoma (PDAC) specimens after preoperative chemoradiotherapy (CRT). METHODS: Among 162 PDAC patients who underwent pancreatectomy after gemcitabine and S1-based CRT from 2012 to 2019, 131 were evaluated for tumor budding. Tumor buds were counted at the invasive front, where the degree of budding was the greatest (hematoxylin and eosin staining, ×20 magnification). Overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS) were compared between the patients without tumor budding (non-TB group) and those with tumor buddings (TB group). Multivariate Cox proportional hazards analysis was conducted to examine the significance of tumor budding as a prognostic factor. RESULTS: OS, DSS, and RFS (median survival time) of the non-TB group were significantly longer than those of the TB group (OS: 50.7 vs. 27.5 months, P = 0.014. DSS: 63.3 vs. 33.0 months, P = 0.014. RFS: 20.3 vs. 11.3 months, P = 0.028). Multivariate analysis identified adjuvant chemotherapy (P = 0.003) as a favorable prognostic factor of OS and tumor budding (P = 0.023) as an adverse prognostic factor of DSS. CONCLUSIONS: This study revealed that the presence of tumor budding was an independent adverse prognostic factor in PDAC patients resected after gemcitabine and S1-based CRT.