Subclassification of Stage IV Gastric Cancer According to the Presence of Distant Metastasis (IVa and IVb)

Ha, Tae Kyung; Kwon, Sung Joon

Abstract

PURPOSE: The TNM staging system showed limitation in stratifying patients into different prognostic groups with gastric cancer. Since the treatment for stage IV gastric cancer with distant metastasis (M1) is defined as non-curative one, we hypothesized that the survival rate of stage IV gastric cancer with M1 is different to that of stage IV gastric cancer with no distant metastasis (M0), which will provide a rationale to subdivide stage IV into IVa and IVb.
MATERIALS AND METHODS
From June 1992 to December 2005, of 1,630 gastric cancer patients who underwent surgery, 308 patients with stage IV gastric cancer were selected and analyzed. The clinicopathologic characteristics and survival of the patients, according to distant metastasis, were determined retrospectively. Median follow-up period was 13 months (range: 1~154 month).
RESULTS
5 year survival rate of M0 and M1 group was 35% and 16% respectively with statistic significance (P=0.0000). When the survival rate of M0 group was analyzed according to the difference of T and M factor, T1-3N3M0 and T4N1-2M0 group showed no significant statistical difference (P=0.1898).
CONCLUSION
Given the result in this study, we suggest that the stage IV gastric cancer be subclassified into stage IVa and IVb according to M factor.