AIM:To investigate the prognostic factors of T4 gastric cancer patients without distant metastasis who could undergo potentially curative resection. METHODS:We retrospectively analyzed the clinical data of 71 consecutive patients diagnosed with T4 gastric cancer and who underwent curative gastrectomy at our institutions.The clinicopathological factors that could be associated with overall survival were evaluated.The cumulative survival was determined by the Kaplan-Meier method,and univariate comparisons between the groups were performed using the log-rank test.Multivariate analysis was performed using the Cox proportional hazard model and a step-wise procedure. RESULTS:The study patients comprised 53 men (74.6%)and 18 women(25.4%)aged 39-89 years (mean,68.9 years).Nineteen patients(26.8%)had postoperative morbidity:pancreatic fistula developed in 6 patients(8.5%)and was the most frequent complication,followed by anastomosis stricture in 5 patients (7.0%).During the follow-up period,28 patients(39.4%)died because of gastric cancer recurrence,and 3(4.2%) died because of another disease or accident.For all patients,the estimated overall survival was 34.1%at 5 years.Univariate analyses identified the following statistically significant prognostic factors in T4 gastric cancer patients who underwent potentially curative resection: peritoneal washing cytology(P<0.01),number of metastatic lymph nodes(P<0.05),and venous invasion(P <0.05).In multivariate analyses,only peritoneal washing cytology was identified as an independent prognostic factor(HR=3.62,95%CI=1.37-9.57)for longterm survival. CONCLUSION:Positive peritoneal washing cytology was the only independent poor prognostic factor for T4 gastric cancer patients who could be treated with potentially curative resection. METHODS: We retrospectively analyzed the clinical data of 71 consecutive patients diagnosed with T4 gastric cancer and who underwent curative gastrectomy at our institutions. Clinicopathological factors that could be associated with overall survival were evaluated. The cumulative survival was determined by the Kaplan-Meier method, and univariate comparisons between the groups were performed using the log-rank test. Multivariate analysis was performed using the Cox proportional hazard model and a step-wise procedure. RESULTS: The study participants were 53 men (74.6%) and 18 women (25.4%) aged 39-89 years (mean, 68.9 years). Nineteen patients (26.8%) had postoperative morbidity: pancreatic fistula developed in 6 patients (8.5%) and was the most frequent complication, followed by anastomosis stricture in 5 patients (7.0%). During the follow-up period, 28 died due of gastric disease recurrence, and 3 (4.2%) died because of other disease or accident. For all patients, the estimated overall survival was 34.1% at 5 years. Univariate analyzes identified the following statistically significant prognostic factors in T4 gastric cancer patients who underwent potentially curative resection: peritoneal washing cytology (P <0.01), number of metastatic lymph nodes (P <0.05), and venous invasion (P <0.05). In multivariate analyzes, only peritoneal washing cytology was identified CONCLUSION: Positive peritoneal washing cytology was the only independent poor prognostic factor for T4 gastric cancer patients who could be treated with potentially curative resection.