1. A method for treating esophageal cancer in situ with a flow of heated air that can be inhaled through a mask and mouthpiece, comprising the steps of: providing and directing the flow of the heated air from a heat source to be inspired/inhaled through a mouth and into a trachea/windpipe, at an elevated temperature less than sauna air temperatures into the trachea of a patient at a sufficient constant positive pressure and temperature to uniformly heat the patient's tracheoesophageal party wall sheath membrane extending between an esophagus and a respiratory trachea in the patient; monitoring and allowing the heated air to heat the patient's tracheoesophageal party wall sheath membrane at a predetermined temperature and constant positive air pressure through the tracheoesophageal party wall sheath membrane to conductively heat the esophageal cancer adjacent to the heated trachea and the tracheoesophageal party wall sheath membrane; whereby the heat provided at the predetermined temperature and at the constant positive pressure from the heated air is inspired by the patient through the trachea migrates/transmits/disperses conductively across the tracheoesophageal party wall sheath membrane separating the patient trachea from the esophagus to contact the esophageal cancer at the predetermined heat and positive pressure sufficient to cause apoptosis programmed cell death thereat, further comprising the steps of: a) providing a heat gun as said heat source; b) installing a correct outlet nozzle on the heat gun; c) determining and adjusting the temperature of the flow of heated air; d) programing and providing the flow of heated air at said constant positive pressure and at a threshold temperature of the esophageal cancer sufficient to remove the esophageal cancer; e) adjusting the output nozzle of said heat gun and supplying said flow of heated air through the patient's mouth and trachea to a location of the tracheoesophageal party wall sheath membrane separating the trachea from the esophagus in the vicinity of the esophageal cancer f) activating said temperature-controlled heat gun with locks and interlocks for a predetermined time, at which time the entire tumor will be conductively heated across the tracheoesophageal party wall sheath membrane from the trachea into the esophagus with heat derived from said flow of heated air at controlled threshold temperatures; and, g) monitoring the cancer temperature for ensuring that the heated air does not exceed a safe temperature threshold within the trachea and esophagus of the patient.