I Am Worried About My Friend. She Has Has GERD

I am worried about my friend. She has has GERD for quite awhile, had an endoscopy last spring and was diagnosed with a hiatal hernia with some scar tissue in her esophagus. Lately though has had problems swallowing, went for another test and a blockage in her esophagus was found. Her doctor told her he is very concerned so he has her going in for an " emergency" endoscopy tomorrow. Could this blockage be a sign of esophageal cancer and if so - would it have developed that quickly after her endoscopy 1 year ago?