They usually can be removed and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body. Most important, benign tumors are rarely a threat to life. Cells in malignant tumors are abnormal and divide without control or order. These cancer cells can invade and destroy the tissue around them.
Cancer cells can also break away and enter the bloodstream or lymphatic system.
This process is called metastasis and is how cancer spreads from the primary site to other parts of the body. Squamous cell carcinomas arise in squamous cells that line the esophagus. These cancers usually occur in the upper and middle part of the esophagus. Adenocarcinomas usually develop in the glandular tissue in the lower part of the esophagus. Both are treated similar.