Proposal to Subclassify Stage IV Gastric Cancer Into IVA, IVB, and IVM

Objective: This study examined the prognosis of patients with stage IV gastric cancer by subgroups after surgical treatment. Design: Retrospective study. Setting: Tertiary care referral center. Patients: A total of 1056 patients with stage IV gastric cancer who underwent gastrectomy from January 1, 1995, through December 31, 2006, were divided into the following 3 groups: T4N1-3M0 (group 1), T1-3N3M0 (group 2), and T(any) N(any) M1 (group 3). Main Outcome Measures: The clinicopathological characteristics, recurrence pattern, and survival were compared among the 3 groups. Results: There was a significant difference in the surgical curability, operation type, Lauren classification, histological differentiation, lymphatic invasion, number of lymph nodes retrieved, and adjuvant therapy among the 3 groups. The 5-year survival rates in groups 1, 2, and 3 were 18.3%, 27.1%, and 9.3%, respectively (P<.001). After R0 resection, locoregional recurrence (40.9%) followed by peritoneal recurrence (27.3%) was most common in group 1, whereas distant (30.2%) and peritoneal recurrence (26.7%) were most common in group 2. Multivariate analysis showed the following significant prognostic factors for survival: surgical curability and adjuvant therapy for group 1; surgical curability, surgical extent, adjuvant therapy, and number of retrieved lymph nodes for group 2; and surgical extent and chemotherapy for group 3. Conclusions: Each subgroup of stage IV gastric cancer had different clinical outcomes, including histological behavior, recurrence pattern, survival, and prognostic factors. Therefore, subclassification of stage IV gastric cancer into IVA (T1-3N3M0), IVB (T4N1-3M0), and IVM (T[any] N[any] M1) might be useful for a more accurate prediction of prognosis and selection of appropriate therapeutic options.