My Mom Had Breast Cancer In 1996 And Had Chemo

My mom had breast cancer in 1996 and had chemo and radiation. In 2012 her esophagus was almost swollen shut and the doctor dilated her esophagus. In 2013 one of her vocal chords was paralyzed and she had a block put in her throat because she was chocking. She also has been diagnosed with acid reflex. Now in 2016 her other vocal chord is paralyzed and her air way is restricted to 5%. Also, now her esophagus is swollen almost completely shut. She has had a CT Scan and it comes back normal, no infection or cancer. Could this be caused by the radiation from the breast cancer treatment? If so, is there a cure?