الفهرس 
ANATOMY OF THE RECTUMOnly 14 pages are availabe for public view
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Abstract
Colorectal cancer is the most common malignancy of the alimentary tract and the rectum is the most frequently involved site, bearing about 35 % of all colorectal tumours.
Two of the main problems of rectal cancer surgery are local recurrence and pelvic autonomic nerve damage. The incidence of sexual dysfunction following conventional rectal surgery ( rectal surgery without consideration of the anatomical planes of the pelvic fascia and pelvic autonomic nerves) about 94 % and bladder dysfunction about 73%.
Adequate removal of the tumour is the first priority of surgery. This goal can be achieved with total mesorectal excision (sharp dissection between the parietal and visceral planes of the pelvic fascia with complete removal of the rectum and mesorectum). Total mesorectal excision procedure is more radical and extensive with preserving the autonomic pelvic nerves. Therefore local recurrence rate, the bladder and the sexual dysfunction decrease.
It is now technically possible to remove rectal cancers that are extending into the anal canal while preserving the anal sphincter mechanism. Ultra-low colorectal and coloanal anastomosis, together with a colonic pouch or coloplsty, ensure acceptable function in many patients.
The local recurrence and survival rate associated with abdominoperineal excision may even be superior to total mesorectal excision either laparoscopic or laporotomy.
Adequate preoperative investigation of the anal sphincter mechanism should prevent the formation of perineal colostomy. Surgeons should perform rectal resection with sphincter preservation wheneven possible for low-lying rectal cancer.
Recently, total mesorectal excision is the operation of choice either laparoscopic or abdominal, it is showing improvement in local recurrence rate. While both conventional rectal cancer surgery and total mesorectal excision result in similarly favourable postoperative bladder function, both techniques decrease sexual function. However, total mesorectal excision offers a significant advantage with regard to preservation of postoperative sexual function in men.
The laparoscopic approach offers several potential benefits over laparotomy, including an earlier return of bowel function, a reduction in hospitalization and better cosmesis.
On the other hand, inadequate excision and increased morbidity are potential risks of a laparoscopic approach. Moreover, sphincter-saving procedures may be compromised because of the technical difficulty in performing stapled low rectal division with the laparoscopic approach, preoperative radiotherapy may also induce difficulties in pelvic dissection.
Short term preoperative radiotherapy for locally advanced tumours is benefit to down sizing and down staging the rectal tumours and to increase the incidence of sphincter saving procedures and also devitalizing tumour cells that might be left behind surgery.
Around 20% of cancers detected during endoscopic screening will be malignant polyps that have only invaded locally and can be removed during endoscopy or by local surgical excision. The other will require open abdominal surgery. At least 50% of colorectal cancers detected at screening will be localized.
Postoperative chemo and radiotherapy followed by early and regular follow up of patients after curative resection by tumor markers, imaging and lower endoscope are important to reach a high cure rates.