الفهرس 
Anatomy of RectumOnly 14 pages are availabe for public view
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Abstract
Worldwide, colorectal cancer represents 9.4% of all incident cancer in men and 10.1% in women. Colorectal cancer, however, is not uniformly common throughout the world. There is a large geographic difference in the global distribution of colorectal cancer. Colorectal cancer is mainly a disease of developed countries with a Western culture. In fact, the developed world accounts for over 63% of all cases. The incidence rate varies up to 10-fold between countries with the highest rates and those with the lowest rates. It ranges from more than 40 per 100, 000 people in the United States, Australia, New Zealand, and Western Europe to less than 5 per 100, 000 in Africa and some parts of Asia. However, these incidence rates may be susceptible to cancer, and these rates change with time. In parts of Northern and Western Europe, the incidence of colorectal cancer may be stabilizing, and possibly declining gradually in the United States.
Laparoscopic resection results in more cosmetic appealing incisions, decreased analgesic requirements, and earlier return of patients to functionality. The use of this minimally invasive surgical technique found its way into colon and rectal surgery. Although it was accepted relatively quickly for surgical treatment of benign disease, the application of laparoscopic technique to colorectal malignancy was initially steeped in controversy because of concerns over port site recurrences and oncologic adequacy. This prompted the initiation of several randomized trials.
In the current stage of minimally invasive surgery, laparoscopic surgery for colon cancer has been established as oncologically equivalent to conventional open surgery. The advantages of laparoscopic surgery have translated into smaller incisions and shorter recovery. However, the narrow confines of the bony pelvis and angling limits in current stapling technology, along with the standard practice of autonomic nerve-sparing total mesorectal excision, have made laparoscopic surgery in the setting of rectal cancer more challenging. The available literature focusing on laparoscopic resection for rectal cancer has been predominantly retrospective in nature, with a limited number of prospective studies.
Basic science research and large randomized controlled trials are now demonstrating that these fears were unjustified. The laparoscopic approach, however, involves a steep learning curve and requires the surgeon and ancillary operating room staff to have advanced skills in laparoscopy.
The number of prospective randomized trials addressing laparoscopic rectal cancer resection is limited. In the largest trial, the UK Medical Research Council (MRC) trial of conventional versus laparoscopic-assisted surgery in colorectal cancer, an initial increased rate of positive circumferential margins within the laparoscopic anterior resection cohort, although non-significant, raised concerns regarding its oncologic adequacy. These concerns did not translate into a difference in local recurrence at 3 years. Improved short-term outcomes, including quicker recovery times, shorter hospital stays, and reduced analgesic requirements (albeit at the price of longer operative times and higher overall cost), have been demonstrated in some studies.