BACKGROUND: In Japan, the incidence of gastric cancer invading the muscularis propria is about 10% of all patients with gastric cancer undergoing surgical resection. Although many prognostic factors for early gastric cancer and advanced gastric cancer have been identified, there are few reports concerning prognostic factors for gastric cancer invading the muscularis propria, and the characteristics of recurrence are not well understood.METHODS: We retrospectively analyzed data on 167 patients with gastric cancer that had invaded the muscularis propria. All patients had undergone curative resection.RESULTS: Recurrences were evident in 37 patients (22.2%). Based on our univariate analysis, the recurrence was associated with lymph node metastases. Multivariate analysis showed that independent risk factors for recurrence were lymph node metastases and location of tumor in the upper or lower one-third of the stomach. With respect to the pattern of recurrence, 17 (46.0%) were secondary to hematogenous recurrence, 8 (21.6%) to peritoneal dissemination, and 6 (16.2%) to a local recurrence in the remnant stomach and in regional lymph nodes. Most deaths occurred during the second year after surgery, and approximately two-thirds of all patients (64.8%) died within 3 years after surgery.CONCLUSION: In patients with the risk factors of lymph node metastases and tumor in the upper or lower one-third of the stomach, lymph node dissection and postoperative adjuvant therapy are vital to try to prevent recurrences, especially during the first 2 years after surgery.