Subclassification of extranodal involvement in gastric cancer patients.

BACKGROUND/AIMS: Extranodal involvement (Ex) has been shown as a negative prognostic factor in several cancers. We classified Ex using 3 methods for gastric cancer and evaluated its influence on patient outcome.

METHODOLOGY

The status of Ex in the 103 node-positive patients with curative resection was classified according to: 1) the number of lymph nodes with Ex, 2) the lymph node grouping system, as specified by the Japanese Classification of Gastric Carcinoma, into Ex confined to compartment 1 lymph nodes and Ex detected in compartment 2 and 3 lymph nodes, and 3) the histological type of tumor cells detected in extranodal metastatic sites.

RESULTS

Ex was observed in 65 of the 103 patients. An increase in the number of lymph nodes with Ex was associated with a significantly poorer outcome. Patients with Ex detected in compartment 2 and 3 lymph nodes had a significantly poorer outcome. The survival rate of patients with two or more histological types was significantly poorer. Multivariate analysis showed that the method 1) and 2) were independent prognostic factors.

CONCLUSIONS

The degree of Ex was shown to be important for determining the prognosis of node-positive gastric cancer patients with curative resection.