This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2018, Subject name: Surgery
[{'content': 'In carcinoma gallbladder stage M1, which of the following lymph nodes are involved? \nSelect and explain. \nA. Superior mesenteric lymph nodes, B. Aoic lymph nodes, C. Celiac lymph nodes, D. Pancreatico-duodenal lymph nodes', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Aoic Lymph node is NOT a regional lymph node.Any metastases detected in these lymph nodes is categorized as distant metastases 8th AJCC (2017) TNM Classification of Carcinoma Gallbladder T1a Lamina propria invasion. T1b Muscular invasion. T2 Invade the perimuscular connective tissue. T2a: Invade the perimuscular connective tissue on the peritoneal side with no extension to serosa. T2b: Invade the perimuscular connective tissue on the hepatic side with no extension into the liver. T3 Serosal perforation and/or direct invasion of the liver (regardless of extent) and/or invasion of any other single extrahepatic organ. T4 Tumor invades the main poal vein, hepatic aery or two or more extrahepatic organ. N1 Metastasis to 1-3 regional nodes. N2 Metastasis to 4 or more regional nodes. M1 Distant metastasis', 'role': 'assistant'}]