Stage II includes: IIA (T3, N0, M0); IIB (T4, N0, M0). T3: Tumor invades through the muscularis propria into the subserosa or into the nonperitonealized perimuscular tissue (mesentery or retroperitoneum) with extension 2 cm or less. T4: Tumor perforates the visceral peritoneum or directly invades other organs or structures (including other loops of small intestine, mesentery, or retroperitoneum more than 2 cm, and abdominal wall by way of serosa; for duodenum only, invasion of pancreas or bile duct). N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 7th ed.) [from NCI]