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': 'Long-term tamoxifen therapy may cause: \nSelect and explain. \nA. Endometrium Ca, B. Ovary Ca, C. Cervix Ca, D. Vagina Ca', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Long-term tamoxifen therapy is a predisposing factor for endometrial hyperplasia and cancers.\nMalignancies caused by Long-term tamoxifen therapy:\n\nCarcinoma endometrium-it is the most common carcinoma associated with it.\nUterine sarcoma.\nRarely liver cancer with a long-term high dose.\n\nNon-malignant effects of tamoxifen on uterus:\n\nEndometrial hyperplasia\nEndometriosis\nFibroid uterus\nOvarian cysts\nMenstrual irregularities or amenorrhea.', 'role': 'assistant'}]