Concurrent lymphovascular and perineural invasion after preoperative therapy for gastric adenocarcinoma is associated with decreased survival.

BACKGROUND AND OBJECTIVES: We sought to evaluate the impact of lymphovascular invasion (LVI) and perineural invasion (PNI) on survival outcomes in gastric cancer patients treated with preoperative therapy. METHODS: Patients with gastric cancer treated with preoperative therapy and potentially curative resection were stratified according to the presence of LVI, PNI, or both. Kaplan-Meier and Cox regression analyses were used to evaluate the impact on overall survival (OS) and disease-free survival (DFS). RESULTS: The study included 281 patients, of whom 93 (33%) had LVI, 69 (25%) had PNI, 51 (18%) had both LVI and PNI, and 170 (61%) had neither. LVI and PNI were each associated with higher ypT and ypN categories and more positive lymph nodes (all p < .001), associations that were emphasized with both factors present. On multivariable analyses, ypN (p < .001) and concurrent LVI/PNI (hazard ratio [HR]: 2.62; 95% confidence interval [CI]: 1.55-4.45; p = .001) were predictive of OS and DFS (ypN: p < .001; both LVI/PNI: HR: 2.27; 95% CI: 1.34-3.82; p = .002). CONCLUSIONS: Gastric cancer patients with concurrent LVI and PNI after preoperative therapy have more advanced disease and worse survival outcomes than patients with neither or only one of these factors.