Tumor Budding and Poorly Differentiated Clusters in Small Intestinal Adenocarcinoma

Area of Science:

• Oncology
• Pathology

Background:

• Tumor budding (TB) and poorly-differentiated clusters (PDC) are emerging prognostic markers in various cancers.
• Their significance in small intestinal adenocarcinomas (SIACs) remains largely uninvestigated.

Purpose of the Study:

• To investigate the clinicopathologic and prognostic significance of TB and PDC in surgically-resected SIACs.
• To evaluate TB and PDC as potential prognostic indicators in SIAC patients.

Main Methods:

• Retrospective analysis of 236 surgically-resected SIAC specimens.
• Quantification of TB (single cells or clusters ≤4 tumor cells) and PDC (clusters ≥5 tumor cells) at peritumoral (p) and intratumoral (i) areas.
• Classification into low-grade (grade-1) and high-grade (grades-2 and -3) based on TB/PDC counts.

Main Results:

• High peritumoral TB (high-pTB) and high intratumoral TB (high-iTB) were observed in 73.7% and 54.7% of cases, respectively.
• High TB/PDC were associated with higher tumor grade, advanced T and N categories, higher stage, and presence of perineural or lymphovascular invasion.
• Multivariate analysis identified high-pTB, nonintestinal type, high N-category, retroperitoneal seeding, and microsatellite-stable status as independent adverse prognostic predictors.
• Subgroup analysis revealed significantly worse survival in early-stage (I-II) patients with high-pTB compared to those with low-pTB (median 42.5 vs. 133.7 months).

Conclusions:

• High TB/PDC, in both peritumoral and intratumoral locations, correlate with aggressive behavior in SIACs.
• High peritumoral TB is a valuable adverse prognostic indicator for SIAC patients, especially in early disease stages.