One option for destroying abnormal cells in your esophagus is called photodynamic therapy. Before the treatment, a light-sensitive medication is injected into a vein in your arm. During the next two days, this medication is absorbed by all the cells in your body. It builds up to a much greater degree in fast-growing cancerous or precancerous cells. Once the medication has been absorbed, your doctor uses an endoscope to guide a laser light down your esophagus to the site of the abnormal cells. The light from the laser activates the light-sensitive medication in the abnormal cells and destroys them. Typically, healthy cells grow back in their place. This procedure may be repeated a number of times, with several months in between treatments.