Chapter 110: Total Mesorectal Excision for Rectal Cancer

BACKGROUND AND HISTORY

Although there have been many advances in the treatment of rectal cancer, including improved imaging, chemotherapy agents, and radiation techniques, none has been more important than advances in surgical technique. Among these advances, total mesorectal excision (TME) is probably the most significant.

In order to appreciate the importance of TME, some history of rectal cancer surgery is in order. At the beginning of the 20th century, the vast majority of patients diagnosed with rectal cancer in Europe and the United States underwent perineal proctectomy. While this operation was an improvement over previous surgeries for rectal cancer, it was a morbid procedure with suboptimal oncologic outcomes.

In 1908 the influential surgeon Sir William Ernest Miles, of St. Mark’s Hospital in London, recognized that, following perineal proctectomy, nearly all of his patients died of recurrent disease within 3 years. On autopsy, he noted that most recurrences were found in the part of the mesorectum that had been left in place and/or within lymph nodes situated near the left common iliac artery. Miles termed these areas the “zone of upward spread.”¹ He concluded that the woeful inadequacy of perineal proctectomy was due to the fact that it failed to address the ultimate cause of local recurrence: incomplete excision of the mesorectum in its entirety, including its lymphovascular supply.

Based on his observations, Miles devised and began immediately to perform a different procedure, which he described as abdominal perineal excision (APE) or abdominoperineal resection (APR), and this soon became the procedure of choice for surgical treatment of carcinoma of the rectum and the terminal portion of the pelvic colon.¹ APR actually involves two procedures performed during the same operation: the abdominal part of the procedure includes dissection of the rectum and mesorectum and creation of a colostomy; the perineal part includes detachment of the rectum and anus from the levators, the genital/urinary organs, and the ischiorectal fat. Compared with perineal proctectomy, mortality and morbidity following this new operation improved dramatically.

Miles’ emphasis on the necessity of removing the mesorectum in its entirety would become the guiding principle of what is now known as total mesorectal excision. Today, TME remains the “gold standard” in the surgical treatment of rectal cancer. As first described by Abel in 1931,² TME entails sharp—rather than blunt—dissection of the visceral and parietal layers of the endopelvic fascia, resulting in intact removal of the rectum and mesorectum. However, the continued common use of traditional blunt dissection limited the benefits of APR, resulting in a 25% rate of positive resection margins and high rates of recurrence and mortality. The absolute necessity of sharp dissection in every APR—meticulously removing the entire mesorectum along the areolar plane outside of the rectal fascia propria—was reemphasized in 1982 by the surgeon Bill Heald.³ Heald⁴ defined TME as an “optimal dissection plane around the cancer which must clear all ...