Neoplastic disorders of the gastrointestinal tract

Collectively, cancers of the gastrointestinal (GI) tract represent a common problem worldwide. Incidence of cancers along the longitudinal axis of the GI tract is variable, with adenocarcinomas of the colon and rectum representing the third most frequent cause of cancer deaths in men and women in the United States, whereas cancers of the small bowel are rare. On the other hand, gastric cancers have decreased in frequency in the United States over the last century; however, they remain a common problem in certain parts of the world such as Asia. This chapter will discuss cancers arising in the GI tract and particularly focus on the pathophysiology and molecular biology contributing to the development of these cancers.