What is the definition or description of: esophageal cancer?

Intraluminal mass: Lesions arising in lumen of the esophagus are considered potentially malignant until bx. As they grow they block lumen causing swallowing problems and then bleed. They occur in 3 regions, the lower third near cardia (adenoCa) of stomach most common and caused frequently by helicon bacter p. Mid esoph follows with squamous lesions and last at upper I/3. RT followed by chemo and surgery used.