Soru

A $58$-year-old man comes to the clinic reporting a $4$-month history of difficulty swallowing. He initially noticed a sensation of food "getting stuck" in his lower chest when eating solid foods such as meat and bread. Over the past few weeks, this sensation has progressed to involve softer foods. The patient also reports an unintentional $6\text{-kg}$ ($13.2\text{-lb}$) weight loss during this period. His past medical history is significant for frequent episodes of burning substernal chest pain over the last $15$ years, which he has managed intermittently with over-the-counter calcium carbonate antacids. He has a $30$-pack-year smoking history. Vital signs are within normal limits. Physical examination reveals a thin, well-appearing man with an unremarkable abdominal exam. Laboratory studies show a hemoglobin of $11.2\text{ g/dL}$ and a mean corpuscular volume of $78\text{ fL}$. Which of the following is the most appropriate next step in management?