Hi, Thanks for writing in. It will help to know which part of the esophagus has developed in to a cancer. The esophagus is divided in to the upper, mid and lower thirds. If there is a cancer in the upper and mid thirds of esophagus then there might be difficulty in swallowing of food and the food stuck can regurgitate and be pushed upwards and make its way in to the airway. This is a concern and can cause choking or get aspirated in to the lungs. Once food particle is aspirated in to the lungs then it can develop in to an infection and pneumonia. This persists and with time can also transform in to severe bacterial infection. There is also a possibility of the airway getting infiltrated by the esophageal growth if there is a large tumor in the upper third of esophagus which is infiltrating in to the airway. Please have a discussion with his doctor to know the actual reason of his difficulty in breathing.