This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Esophagus, Subject name: Surgery
In Esophageal cancer prognosis is best determined by: 
Select and explain. 
A. Cellular differentiation, B. Age of patient, C. T stage, D. Length of involvement
C: T stage
Answer: C: T stage 
Explanation: Prognosis Long term survival following esophagectomy depends on - Depth of tumor invasion (T) - Number of involved lymph nodes (N) - Location of the tumor in the esophagus Prognosis is better for tumors of the cervical esophagus and at GE junction, in comparison to tumors located in the thoracic esophagus.