[Effect of lymphatic vascular invasion on the prognosis of stage I( gastric cancer patients after radical gastrectomy].

OBJECTIVE: To investigate the prognostic value of lymphatic vascular invasion (LVI) for stage I( gastric cancer patients after radical gastrectomy.

METHODS: Clinicopathological and intact follow-up data of 469 stage I( gastric cancer patients who underwent radical gastrectomy with R0 resection and were pathologically proven as gastric adenocarcinoma without other malignancy at the Department of Digestive Surgery, The First Affiliated Hospital, The Fourth Military Medical University between February 2009 and December 2012 were retrospectively collected. Chi square test was used to examine the relationship between LVI and clinicopathological data; Log-rank test was used for survival analysis; Cox proportional hazards model was used for univariate and multivariate analysis to explore the prognostic influence of LVI on stage I( gastric cancer patients.

RESULTS: A total of 469 patients were enrolled, including 360 male (76.8%) and 109 female patients (23.2%). Median age was 58(25-82) years. There were 114 T1a cases (24.3%), 195 T1b cases (41.6%), and 160 T2 cases (34.1%). There were 439 (93.6%) cases without lymph node metastasis and 30 cases with lymph node metastasis. Presence of LVI was found in 52 patients (11.1%). LVI was closely associated with tumor grade, depth of invasion and status of lymph node metastasis (all P<0.05), rather than gender, age, tumor location and tumor diameter (all P>0.05). LVI detection rate was higher in poorly differentiated and undifferentiated group (14.3%, 32/223) than that in moderately and well differentiated group (8.1%, 20/246) (χ2 =4.590, P=0.032). LVI detection rate was higher in T2 (14.4%, 23/160) and T1b (13.3%, 26/195) group than that in T1a group (2.6%,3/114)(χ2 =11.020, P=0.004). LVI detection rate was higher in patients with lymph node metastasis (30.0%, 9/30) compared to those without lymph node metastasis (9.8%, 43/439) (χ2 =11.629, P=0.001). Median follow-up time was 63(3-74) months. There were totally 46 deaths (9.8%). The 5-year overall survival rate was 90.2%. The 5-year overall survival rate was 82.7% in patients with LVI and 91.1% without LVI, which was significantly different (P=0.039). Univariate analysis showed that age (P=0.012), AJCC T stage (8th edition) (P=0.011), and LVI (P=0.043) were closely associated with the prognosis of gastric cancer patients, while gender, tumor location, tumor diameter, tumor grade, lymph node metastasis or postoperative chemotherapy were not associated to the prognosis (all P>0.05). Multivariate analysis revealed that only age(HR=2.038, 95%CI:1.126 to 3.686, P=0.019) and advanced T stage (T1b: HR=1.427, 95%CI:0.554 to 3.678; T2: HR=2.926, 95%CI:1.199 to 7.140; P=0.017) were independent prognostic factors of stage I( gastric cancer patients (both P<0.05).

CONCLUSIONS: LVI is not an independent prognostic factor of stage I( gastric cancer patients. In clinical practice, we should consider adjuvant chemotherapy prudently for stage I( gastric cancer patients with LVI.