Curative resection, including gastrectomy, extensive lymph node dissection, and combined resection of invaded organs, is the mainstay of treatment for T4b gastric cancers. We sought to investigate the clinicopathologic features, surgical outcomes, and prognostic factors of curatively resected pathologic T4b gastric cancer with a focus on organs invaded.

Data of 243 pT4b gastric cancer patients who underwent curative resection at Korea Cancer Center Hospital from 1991 to 2005 were retrospectively subjected to univariate and multivariate analyses.

Overall 5-year survival rate and median survival time were 36.8% and 26 months, respectively. Five-year survival rates were 23.3% in the pancreatic invasion group (n = 67) and 42.1% in the nonpancreatic invasion group (n = 176) (P = 0.002). Regarding operative methods used for pancreatectomy in pancreatic invasion group, 5-year survival rates were 0% in the pancreaticoduodenectomy group (n = 9) and 27.4% in the other pancreatectomies group (n = 58) (P = 0.013). Multivariate analysis revealed that advanced lymph node stages (hazard ratio [HR] 1.637 for N0 vs. N1, HR 2.177 for N0 vs. N2, HR 3.241 for N0 vs. N3a, and HR 4.000 for N0 vs. N3b), encircling type of tumor (HR 1.804), and pancreatic invasion (HR 1.463) were independently unfavorable prognostic factors.

In pT4b gastric cancer, pancreatic invasion was found to portend the least favorable prognosis, especially in cases requiring pancreaticoduodenectomy. However, prognoses were more favorable after curative resection in patients without advanced lymph node stages (N2, N3a, and N3b), an encircling type of gastric tumor, or pancreatic invasion. We propose a novel therapeutic strategy for patients with T4b gastric cancer.