pN3M0 gastric cancer: The category that allows the sub-classification of stage-IV gastric cancer (IVa and IVb)

Background: Since the publication of the fifth edition of the UICC TNM classification, the rate of curative surgical resection for stage-IV gastric cancer has increased. It is related to the N3 category, which was the prior pN1 or pN2 in the fourth UICC TNM staging system and now pN3 in the fifth. We performed a retrospective analysis to determine whether the prognosis of N3M0 gastric cancer is different from that of other stage-IV gastric cancer; this may support sub-division of this disease. Methods: We analyzed 422 patients with stage-IV gastric cancer who underwent gastric resection from 1983 to 2002 at Korea University Hospital. Clinical and pathological characteristics as well as survival of the patients were evaluated retrospectively according to the TNM categories. Results: The 5-year survival rate for those with N3M0 gastric cancer was 10.5%; this was influenced by depth of invasion (P = 0.001). According to the survival analysis in patients with stage-IV subtypes, the mean survival time was 25.6 months for T1-3N3M0, 24.7 months for T4N1-2M0, 10.0 months for T4N3M0, and 13.6 months for anyT anyNM1. Thus, the survival of patients with T4N3M0 and M1 stage disease was significantly shorter than that of patients with T1-3N3M0 and T4N1-2M0 stage disease (P = 0.000). Conclusions: Sub-classification of stage-IV gastric cancer into IVa (T1-3N3M0, T4N1-2M0) and IVb (T4N3M0, anyT anyNM1) may be helpful to predict the outcome of patients with stage-IV gastric cancer.