Prognostic Significance of Splenic Vein Invasion for Pancreatic Cancer Patients With Pancreatectomy: A Retrospective Study.

Background/aim: This study aimed to clarify the prognostic significance of splenic vein (SpV) invasion in patients with pancreatic cancer, which is not currently included in the anatomical resectability classification, compared with that of portal vein (PV) and/or superior mesenteric vein (SMV) invasion.

Patients and methods: A total of 188 patients with pancreatic cancer who underwent macroscopic radical pancreaticoduodenectomy (n=107) or distal pancreatectomy (n=79) were analyzed. The characteristics and prognosis of patient with SpV invasion were analyzed and compared with those of patients with PV/SMV invasion or without PV system invasion.

Results: Patients with SpV invasion had a more advanced tumor status, such as large tumor size and arterial invasion. Consequently, they included relatively more patients with microscopically residual tumors than those without PV system invasion. The prognosis of patients with SpV invasion was equivalent to that of patients with PV/SMV invasion (p=0.816) and significantly worse than that of the non-invasive group (p=0.015). SpV invasion was also an independent poor prognostic factor in multivariate analysis (p=0.042). Additionally, the prognosis of patients with SpV invasion was notably better when they underwent preoperative chemotherapy compared to those who did not (p=0.018). This finding represents a significant distinction from patients with PV/SMV invasion or those without PV system invasion.

Conclusion: Although SpV invasion is not classified as an anatomically unresectable/borderline-resectable factor, it is a significantly poor prognostic factor, similar to PV invasion. Additionally, patients with SpV invasion may benefit more from neoadjuvant chemotherapy than those with PV/SMV invasion or other advanced cancers.