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: Surgery
[{'content': 'True about melanoma of the anal canal is - \nSelect and explain. \nA. Present usually as anal bleeding, B. AP resection gives better result than local excision, C. Local recurrence at the same site after resection, D. Radiosensitive', 'role': 'user'}, {'content': "Answer: A \nExplanation: The anal canal is the third most common site for melanoma, following skin and eye.\nIt's a rare tumor comprising less than 1% of anorectal malignancies.\nIt is radioresistant and prognosis is very poor.\n\nClinical presentation\n\naverage age is 50 to 60 yrs.\nnonspecific symptoms are seen → bleeding, pain or anal mass.\nusually misdiagnosed as thrombosed hemorrhoids.\n\nTreatment\n\nMelanoma is resistant to chemotherapy & radiotherapy\nSurgery offers the only cure but by the time the symptoms appear, the level of invasion precludes surgical cure in most patients. In these patients, the disease has metastasized or is deeply invasive.\nA few patients present with isolated local or locoregional disease that is potentially resectable for cure.\nThe two surgical procedures used are\n\nWide local excision and APR\n\nRecurrence is common and usually occurs systemically regardless of the initial surgical procedure. Local resection does not increase the risk of local or regional recurrence and APR offers no survival advantage over local excision. Because of the morbidity associated with APR, wide local excision is recommended for initial t/t of localized melanoma. APR may be required if the tumor involves a significant portion of the anal sphincter or is circumferential.", 'role': 'assistant'}]