Colon cancer

Cancers of the colon represent the third leading cause of neoplasia-related morbidity and mortality in the United States and Canada (Committee CCSS 2009; Jemal et al. 2009). The lifetime risk for colon cancer is estimated to be 1 in 20 persons, with a median age of diagnosis of 71 years (Jemal et al. 2009). Over the past three decades, the overall incidence of colon cancer has diminished slightly by 2.2% in women and 2.8% in men (Jemal et al. 2008), yet there has been an increasing relative incidence of proximal, particularly cecal, colonic adenocarcinoma (Troisi et al. 1999). While this is partly explained by increased endoscopic screening, the etiology of this proximal shift is not entirely understood. Encouragingly, 5-year survival rates have notably improved over this time period, from 52% in 1975 to 65% in 2004 (Jemal et al. 2009).