Correlation of histological heterogeneity and lymph node metastasis in gastric adenocarcinoma

Abstract

AIM: To study the possible correlation between the intratumor histological heterogeneity and degree of lymph node metastasis in gastric adenocarcinoma and to explore the clinical significance of histological heterogeneity in gastric adenocarcinoma. METHODS: Tumor specimens were collected from 138 gastric adenocarcinoma cases in which lymph nodes were also checked. All tumor specimens were consecutively cut into serial sections and examined by microscope. The intratumor histological heterogeneity was defined by finding of at least two histological subtypes. Total number of metastatic lymph nodes was counted. And staging was conducted according to the classification of UICC/ AJCC standard. The N stage distributions of intratumor histological heterogeneity were examined and compared. RESULTS: The incidence of intratumor histological heterogeneity was 58.7% in 138 specimens of gastric adenocarcinoma. It was two-subtype histological heterogeneity that were found in most positive specimens (69/81, 85%). More than half of them were of glandular plus poorly differential types (42/69, 60.9%). A total of 8568 lymph nodes were found in 138 cases (average 62.1). 33 cases of N0, 36 N1, 29 N2 and 40 N3 were identified according to the N classification of UICC/ AJCC standard. Intratumor histological heterogeneity was found in 36% of the N0 group and 80% of N3 group. Distribution of intratumor histological heterogeneity displayed difference among the N stages, which was of high statistical significance (χ 2 =14.86, P 0.05). CONCLUSION: The intratumor histological heterogeneity can be seen as a frequent event in gastric adenocarcinoma (58%). Intratumor histological heterogeneity is found evidently correlated with lymph node metastasis in gastric adenocarcinoma.