Acquisition of histologic diversity contributes to not only invasiveness but also lymph node metastasis in early gastric cancer.

BACKGROUND

As more endoscopic resections are performed in early gastric cancer, the pretreatment prediction of lymph node metastasis (LNM) becomes more important. Some tumor characteristics including histologic type, invasion depth, ulceration, size, and lymphovascular invasion have been used to determine the endoscopic resectability of early gastric cancer; however, a more detailed analysis between clinicopathologic factors and lymph node metastasis is needed.

METHODS

We analyzed the correlation between the clinicopathological findings and LNM with 310 cases of early gastric cancer by dividing invasion depths in detail.

RESULTS

LNM occurred in 3.2% and 16.2% of the T1a and T1b tumors, respectively. LNM was associated with invasion depth (p=0.002) and lymphatic (p<0.001) and perineural (p=0.013) invasion. Among them, lymphatic invasion was the most powerful factor associated with LNM and significantly constant in T1a and T1b. The rate of LNM increased gradually as the tumor invaded deeper, and invasion of the muscularis mucosae layer was associated with an increased mixed adenocarcinoma incidence, suggesting that histologic diversity was associated with tumor invasiveness.

CONCLUSIONS

We demonstrated that lymphatic invasion was the most important and powerful parameter for LNM in early gastric cancers. In addition, tumor invasiveness into the muscularis mucosae was accompanied by tumor histologic diversity.