Tumor Biological Aspects of Epithelial versus Mesenchymal Tumors of the Gastrointestinal Tract.

One of the holy grails of cancer surgery for surgical oncologists is to perform a macroscopically complete resection of the affected organ or site with negative microscopic margins. The surgical oncologist must also be mindful of what constitutes appropriately-sized negative margins. However, what is necessary, based on the best available evidence, can vary considerably for different malignancies arising within the same organ. This review compares two different gastric and rectal malignancies, one each of epithelial and of mesenchymal origin. Data supporting extent of margins will be reviewed, illustrating the importance of knowing the histologic diagnosis prior to surgery to provide proper oncologic care.