Prognostic Impact of Portal System Invasion in Pancreatic Cancer Based on Image Classification

This study aimed to clarify the correlation between image classification and the pathological degree of portal system invasion (PSI) and to evaluate the prognostic impact of PSI in pancreatic cancer (PC).

Pancreatic cancer patients with surgical resections (head, n = 244; body and tail, n = 80) were enrolled in this study.

Based on imaging findings, portal vein (PV) invasion was classified as type A (absent), B (unilateral narrowing), C (bilateral narrowing), or D (stenosis or obstruction with collaterals). Splenic vein (SPV) invasion was classified as type α (absent), β (stenosis), or γ (obstruction). The pathological grade of venous invasion was classified as grade 0 (no invasion), 1 (tunica adventitia), 2 (tunica media), or 3 (tunica intima). In PV and SPV invasions, image classification and pathological grade showed significant correlation (PV: ρ = 0.696; SPV: ρ = 0.681). Patients with PV invasion deeper than type B exhibited significantly poorer survival than type A (P < 0.0001). In contrast, there was no difference in survival among types α, β, and γ.

Image classification was correlated with the pathological grade of PSI in PC. Although not applicable for SPV invasion, image classification of PV invasion is a robust indicator for PC prognosis.