This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'The stage of cancer endometrium with invasion of 10 mm of myometrium is: \nSelect and explain. \nA. Ia, B. Ib, C. IIb, D. IIa', 'role': 'user'}, {'content': 'Answer: B \nExplanation: According to older staging\n\nIf tumor involves myometrium, it belongs to either stage Ib or Ic. Normal thickness of myometrium is 10-20 mm, therefore, if 10 mm of myometrium is involved. It should ideally be included in stage Ic but since Ic is not given in options, IInd best option is lb.\nNow if we think from newer revised staging it says\nIn stage IA-Tumor is confined to uterus and either it is limited to endometrium or less than half of myometrium is involved.\nStage IB-Tumor confined to uterus with more than or equal to half of myometrial invasion\nThickness of 10 mm means more than half of myometrium, i.e. stage lb.', 'role': 'assistant'}]