Prognostic significance of the concomitant existence of lymphovascular and perineural invasion in locally advanced gastric cancer patients who underwent curative gastrectomy and adjuvant chemotherapy.

OBJECTIVE In this study, we evaluated the prognostic significance of the concomitant existence of lymphovascular invasion and perineural invasion in patients with advanced gastric cancer. METHODS A total of 206 consecutive patients with Stage II or III gastric cancer who underwent curative D2 gastrectomy and adjuvant chemotherapy from April 2004 to December 2011 were analyzed. Patients were classified into four groups according to the presence (+) or absence (-) of lymphovascular invasion and perineural invasion: lymphovascular invasion-/perineural invasion- (n = 33), lymphovascular invasion+/perineural invasion- (n = 31), lymphovascular invasion-/perineural invasion+ (n = 54) and lymphovascular invasion+/perineural invasion+ (n = 88). RESULTS A total of 136 patients (66.0%) received 5-fluorouracil plus cisplatin adjuvant chemotherapy and 70 patients (34.0%) received TS-1. During the median follow-up period of 35.18 months, the median disease-free survival times for lymphovascular invasion-/perineural invasion-, lymphovascular invasion+/perineural invasion- and lymphovascular invasion-/perineural invasion+ were not reached at the time of analysis; however, median disease-free survival for lymphovascular invasion+/perineural invasion+ was the worst (36.73 months, P = 0.001). The median overall survival in the four groups was also not reached at the time of analysis; however, median overall survival with lymphovascular invasion+/perineural invasion+ was the poorest (P = 0.002). In a multivariate analysis, lymphovascular invasion+/perineural invasion+ was an independent prognostic factor for both disease-free survival (hazard ratio = 1.940, 95% confidence interval 1.157-3.252, P = 0.012) and overall survival (hazard ratio = 2.973, 95% confidence interval 1.561-5.662, P = 0.001). CONCLUSIONS The concomitant existence of lymphovascular and perineural invasion has a significant prognostic impact on disease-free survival and overall survival in patients with Stage II or III gastric cancer.