Analysis of clinicopathologic factors affecting formation of lymphovascular invasion in 1 260 patients with gastric cancer

Abstract

Objective To analyze the clinicopathologic factors affecting the formation of lymphovascular invasion (LVI) in patients with gastric cancer. Methods The retrospective case-control study was conduted. The clinicopathologic data of 1 260 patients with gastric cancer who were admitted to the First Affiliated Hospital of Nanjing Medical University between January 2014 and December 2015 were collected. All the surgical specimens of patients were detected by hematoxylin-eosin (HE) stain and diagnosed by pathological experts. Stages of patients were evaluated by the seventh TNM staging system for gastric cancer of American Joint Committee on Cancer (AJCC) and Union for International Cancer Control (UICC). Observation indicators: (1) pathologica features: histological differentiation, invasive depth, lymph node metastasis and TNM staging; (2) follow-up situations; (3) influenced factors of the positive LVI: sex, age, histological differentiation, invasive depth, number of lymph node metastasis and TNM staging affecting positive LVI were analyzed. Follow-up using outpatient examination and telephone interview were performed to detect survival of patients up to June 2016. Univariate analysis was done using the chi-square test, and multivariate analysis was done using the trend chi-square test, and binary Logistic regression model. Results (1) Pathological features: 1 260 patients with gastric cancer were diagnosed by postoperative pathological examinations, including 355 with positive LVI and 905 with negative LVI. Histological differentiation: high-differentiated tumor was detected in 13 patients, moderate-differentiated tumor in 232 patients and low-differentiated tumor in 775 patients. There were 95 patients with mucinous adenocarcinoma and 145 with signet-ring cell carcinoma. Invasive depth: tumor invasion into mucosal layer or submucosal layer (T1 stage) was detected in 242 patients, muscular layer (T2 stage) in 160 patients, gastric wall layer and no invasion into serosal layer (T3 stage) in 37 patients and subserosal layer (T4 stage) in 821 patients. Lymph node metastasis: no regional lymph node metastasis (N0 stage) was detected in 461 patients, 1-2 lymph nodes metastases (N1 stage) in 164 patients, 3-6 lymph nodes metastases (N2 stage) in 245 patients and more than 7 lymph nodes metastases (N3 stage) in 390 patients. TNM staging: there were respectively 191 patients in ⅠA stage, 114 in ⅠB stage, 62 in ⅡA stage, 202 in ⅡB stage, 132 in ⅢA stage, 80 in ⅢB stage, 476 in ⅢC stage and 3 in Ⅳ stage. (2) Follow-up situations: 1 142 patients (320 with positive LVI and 822 with negative LVI) were followed up for 4.0-24.0 months, with a meidan time of 11.0 months and a follow-up rate of 90.635% (1 142/1 260). During the follow-up, 154 patients died, including 41 with positive LVI and 113 with negative LVI. (3) Influenced factors of the positive LVI: ① results of univariate analysis showed that histological differentiation, invasive depth, number of lymph node metastasis and TNM staging were factors affecting positive LVI of patients with gastric cancer (χ2=16.930, 29.190, 64.463, 46.539, P<0.05). ② Results of the trend chi-square test showed that histological differentiation, invasive depth, number of lymph node metastasis and TNM staging were factors affecting positive LVI of patients with gastric cancer, with a linear correlation (χ2=54.883, 69.130, 164.618, 119.594, r=0.211, 0.243, 0.365, 0.316, P<0.05). There was a greater correlation between number of lymph node metastasis and formation of lymphovascular invasion. ③ Results of the binary Logistic regression model showed that moderate- and low-differentiated tumor and N1-N3 stage of lymph node metastasis were independent risk factors affecting positive LVI of patients with gastric cancer (OR=2.572, 1.782, 95% confidence interval: 0.495-1.494, 0.386-0.781, P<0.05). Conclusion Patients with lower tumor differentiation and / or greater number of lymph node metastasis may have a higher risk of forming LVI. Key words: Gastric neoplasms; Lymphovascular invasion; Number of lymph node metastasis