Prognostic prediction in gastric cancer patients without serosal invasion: comparative study between UICC 7(th) edition and JCGS 13(th) edition N-classification systems.

OBJECTIVE: T-stage and N-stage have been proven to be the most important factors influencing survival in gastric cancer patients, and have been accepted for use in the Japanese Classification of Gastric Carcinoma (JCGC) and the Union International Cancer Control (UICC-TNM) staging systems. The purpose of this study was to compare the prognostic values of the different N classification systems in gastric cancer patients without serosal invasion.
METHODS: We retrospectively compared the clinicopathological results of 1,115 patients with primary gastric cancer who underwent curative gastric resection.
RESULTS: Serosal invasion was identified in 212 of 1,115 patients (19.0%), and it was associated with lymph node metastasis according to the JCGC(13th) (P<0.001) and TNM(7th) (P<0.001) systems. The 5-year survival rate for the serosal invasion-negative patients (78.2%) was significantly higher than that for the serosal invasion-positive patients (31.1%) (P<0.001). Multivariate Cox regression survival analysis showed that depth of invasion (P=0.013), 13(th) JCGC PN stage (P<0.001), and 7(th) TNM PN stage (P<0.001) were independent prognostic factors for serosal invasion-negative gastric cancer patients.
CONCLUSIONS: The prognosis of gastric cancer patients with serosal invasion is very poor. Both the 13(th) JCGC and 7(th) TNM N-staging systems were able to accurately estimate the prognosis of gastric cancer patients, but the 7(th) TNM system was simpler and easier to use.