This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Neoplasia), Subject name: Surgery
[{'content': 'To differentiate malignancy from benign lesion in GIT, investigation of choice: \nSelect and explain. \nA. USG, B. Biopsy, C. Endoscopy, D. P.E.T scan', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) BiopsyRef: Chapter 91: Harrison 18th ed.* Taking multiple biopsies increases the yield. Cytologic examination of tumor brushings complements standard biopsies and should be performed routinely.* The extent of tumor spread to the mediastinum and para-aortic lymph nodes should be assessed by CT scans of the chest and abdomen and by endoscopic ultrasound.* Positron emission tomography scanning provides a useful assessment of resectability, offering accurate information regarding spread to mediastinal lymph nodes', 'role': 'assistant'}]