INCIDENCE AND EPIDEMIOLOGY
At the beginning of the 21st century, rectal cancer continues to be a significant medical and social problem. Currently, there are approximately 135,000 cases of colorectal cancer diagnosed in the United States each year and 50,000 deaths. Approximately 60% of all cases occur in patients older than 65 years of age. Cases that occur prior to age 65 this include 45% of men and 39% of all women diagnosed with colorectal cancer. Significant racial disparities also exist in the incidence and mortality for colorectal cancer, with non-Hispanic blacks (NHB) having the highest incidence and mortality. When compared to non-Hispanic whites (NHW), the NHB population has a 20% higher incidence of colorectal cancer and a 40% higher mortality rate. Overall survival is higher for patients with rectal cancer (67%) than colon cancer (64%), with the most likely explanation being that rectal cancer is more often diagnosed at an earlier localized stage.
Overall, 40% of colorectal tumors are in the proximal colon and 60% are in the distal colon and rectum. However, women are more likely to have proximal lesions (46%) when compared to men (37%), and this disparity increases with advancing age. At younger ages (less than 50), both men (41%) and women (36%) are more likely to be diagnosed with rectal than colon cancer. In fact, there has been a substantial absolute increase in the risk of rectal cancer in patients born after 1970. The reason for the increased risk for rectal cancer in this young population has not been identified but is most likely related to a change in environment, either an exogenous exposure or ingested material in foods such as pesticides or food additives. Increases in the sedentary lifestyle, high-fat diet, and obesity have been suggested etiologic factors as well. As pointed out above, adenocarcinoma of the rectum accounts for nearly 30% of all colorectal cancers. This translates into about 41,000 new diagnoses of rectal cancer each year and greater than 10,000 deaths attributable to this disease within the same time.1,2
The history of modern rectal cancer resection dates to 1884, when Czérny described the first abdominoperineal resection (APR). In 1885, Kraske pioneered the transsacral approach of rectal resection and anastomosis. In 1908, Miles improved on the APR by understanding that there was a “zone of upward spread.”3 He emphasized the importance of performing a wide perineal excision. Consistent with this, current surgical technique includes a cylindrical resection at the level of the levators to include the entire anal canal such that there is not a “coning in” or “waist” on the specimen at the distalmost aspect of the specimen. Furthermore, Miles advocated removal of the rectum with a high ligation of the superior hemorrhoidal artery as well as excision of the abdominal attachments of the rectum and the iliac lymph nodes. Despite the improvements in oncologic resection, operative mortality in Miles’ first ...