After a workup by your primary physician or gastroenterologist (stomach and intestine specialist), you will have to go for surgical consultation.
A thorough clinical history has to be elicited and a physical examination has to be done. Your surgeon will discuss with you your diagnosis and if surgery is indicated for you. You may need to undergo further testing before a decision can be made. If the diagnosis is cancer, you will also be referred to an oncologist.
You will undergo preoperative testing including lab work, chest x-ray and other imaging examinations.
Depending on your situation, your doctor may talk with you about possible surgeries. The final decision will be made by you and your gastroenterologist and surgeon.