This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diagnostic Evaluation of the Esophagus, Subject name: Surgery
[{'content': 'All the following statement regarding this radiological film representing esophagus is true except? \nSelect and explain. \nA. Squamous cell usually affects the upper two-thirds, B. Adenocarcinoma usually affects the lower-third, C. Lymph node involvement is a bad prognostic factor, D. Dysphagia is the most common and early presenting symptom', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (d) Dysphagia is the most common and early presenting symptom.Carcinoma of the esophagus* Squamous cell usually affects the upper two-thirds; adenocarcinoma usually affects the lower-third* Common etiological factors are tobacco and alcohol (squamous cell) and GORD (adenocarcinoma)* The incidence of adenocarcinoma is increasing* Lymph node involvement is a bad prognostic factor* Dysphagia is the most common presenting symptom, but is a late feature* Accurate pretreatment staging is essential in patients thought to be fit to undergo \'curative\' treatmentImage source- style="font-family: Times New Roman, Times, serif">', 'role': 'assistant'}]