LAUSR

Objective. Tumour budding and desmoplastic reactions in peritumoural stroma are features of the tumour microenvironment that are associated with colorectal cancer prognosis but have not been as thoroughly examined in gastric cancer. We aimed to further characterize the prognostic role of tumour budding and desmoplastic reaction in gastric adenocarcinoma with intestinal differentiation. Methods. 76 curative gastrectomy specimens were identified, excluding post-neoadjuvant cases or cases with >50% diffuse-type histology. Tumour budding was defined and graded according to the International Tumor Budding Consensus Conference recommendations and desmoplastic reaction was classified as described by Ueno et al 2017. Tumour budding and desmoplastic reaction were analyzed for associations with pathologic features and clinical outcomes. Results. Tumour budding was associated with pT (P < .001), pN (P < .004), overall stage (P < .001), LVI (P < .001) and PNI (P = .002). Desmoplastic reaction was associated with pT (P < .001), pN (P = .005), overall stage (P = .031) and PNI (P < .001), but not LVI. Survival analysis showed decreased overall survival (OS) and recurrence-free survival (RFS) for intermediate and high grade tumour budding (P = .031, .014 respectively). Immature stroma was significantly associated with RFS but not OS. Neither tumour budding nor desmoplastic reaction were independent predictors of OS or RFS on multivariate analysis in this cohort. Conclusion. Tumour budding and desmoplastic reaction were associated with known pathologic risk factors. Prognostically, tumour budding was associated with OS and RFS while desmoplastic reaction was associated with RFS only. Our data suggest that tumour budding and desmoplastic reaction have prognostic value in intestinal-type gastric adenocarcinoma.