Esophageal cancer: A malignant tumor of the esophagus. The risk of cancer of the esophagus is increased by long-term irritation of the esophagus, such as from smoking, heavy alcohol intake, and Barrett esophagitis. Very small tumors in the esophagus usually do not cause symptoms. As a tumor grows, the most common symptom is difficulty in swallowing. There may be a feeling of fullness, pressure, or burning as food passes down the esophagus. Cancer of the esophagus can also cause indigestion, heartburn, vomiting, and frequent choking on food. Because of these problems, weight loss is common. Esophageal cancer can be diagnosed through a barium X-ray study of the esophagus and endoscopy and biopsy of the tumor. Treatment includes chemotherapy and sometimes surgery.