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|05-30-2008, 04:05 PM||post no: 1|
CANCER RECTUM (Precancerous Lesions-Pathology-Clinical picture-Complications-Treatment)
Sex: males > females it is the commonest CA of large intestine.
q Precancerous Lesions:
1) Benigen tumours: Villous papilloma, adenomatous polyp, familial polyposis, and Gardner's syndrome.
2) Ulcerative colitis.
q Macroscopic picture:
(1) Cauliflower (polypoid type) common in the ampulla of rectum.
(2) Infiltrative (annular type)common in the rectosigmoid junction "commonest site"
(3) Ulcerative type:commonest in lower part and anal canal but it may occur at any site.
q Microscopic picture:
(1) Adenocarcinoma of different grades of differentiation.
(2) Squamous cell carcinoma from the anal canal.
(3) Malignant melanoma may develop in the anorectal juncton.
(4) Carcinoid tumour of the rectum
(I) Direct spread: In transverse direction, it infiltrates 1/4 of the circumference in 6 months.
(II) Lymphatic spread: see before
(III) Blood spread: mainly to the liver.
(IV) Peritoneal spread: in advanced cases.
Duke classify CA. rectum according to its spread (Duke's classification) into:
1) Group A, tumour is confined to rectal wall with best prognosis after surgical excision.
2) Group B, Extra rectal tissue involvement. But with no lymph nodes.
3) Group C, lymph nodes are involved:
C1: only pararectal lymph nodes are involved.
C2: involvement of inf. mesenteric gl. (site of ligation) ® worse prognosis.
4) Group D, distant metastases are present ® inoperable cases.
q Cl. picture:
(1) Upper 1/3 (Rectosigmoid junction): obstructive manifestation as:
- Progressive constipation "ch. obstruction" ® Acute obstruction on top of chronic ® fermentation of accumulated faeces which become fluid with acid production ® irritation of the colon ® Spurious diarrhea.
(2) Middle 1/3 (Ampulla of rectum):
- Tenesmus (false desire for defecation)
- Mucus + blood / rectum.
(3) Lower 1/3 (ano rectal junction):
The anal canal contains pain receptors so, pain is an early presentation which may be due to infiltration of nerves or superadded infection. Infiltration of sacral plexus may give pain of sciatica.
(1) P.R.: Alone can diagnose 90% of cases. you must detect the level, size and mobility.
(2) Endoscopy: By proctoscope and sigmoidoscop to take biopsy.
(3) Barium enema: not needed except in diagnosis of another lesions in the colon.
(4) Carcino-embryonic Antigen: In follow up more than in diagnosis.
(5)Trans-rectal ultrasonography: help in assessment of invasion of the wall.
qTreatment:The earlier the diagnosis and the more the radicality in resection, the better the prognosis.
(I) Operable Cases:
· Preoperative preparations: The same as that mentioned in cancer colon. (Chemical and mechanical preparation) see before.
1- Radical resection of the tumour: We remove:
a- Anal canal & perianal tissue, Rectum & perirectal tissue & sigmoid colon.
b- Lymph drainage groups upward, laterally, and downward.
* The upward glands are the most important.
* In CA. anal canal bilateral inguinal L.N. dissection is done.
Ended by terminal colostomy.
The radical resection is done by one of the following:
a) Abdomino perineal resection of "Miles"
- One surgeon open the abdomen 1st then resect the anal canal perineally.
b) Perineo-abdominal resection of "Gabreil".
- One surgeon resect the anal canal at 1st then open the abdomen.
c) Combined resection.
- Two surgeons work together to shorten the time and minimize the complications.
2- Sphincter- Saving Operation (Anterior resection) :
a) High tumours" upper 2/3 of the rectum"
b) Well differentiated tumours.
Ÿ Technique: The sigmoid colon and rectum 2 cm below the tumour margin are excised. The anal canal and 3cm of the rectum is preserved and anastomosed with the colon.
3- Laparoscopic resection: With improvement in the technology such procedure may become more common. Neverthless, there is concern that these operations may be less curative than standard operations.
4- Radical pelvic exenteration: In addition to the structures removed in abdominoperineal resection, we remove the urinary bladder and lower ureters and seminal vesicles in male, and uterus, vagina and ovaries in female with terminal clostomy and ureterostomy
(II) Inoperable Cases:
1- If resectable ® Do palliative resection.
2- If irresectable ® Colostomy to bypass the obstruction.
® Radio and chemotherapy.
® Morphia to releive the pain.
SOURCE: DR. AYMAN SALEM'S BOOK
Copyright: Vascular Society of Egypt (www.vsegypt.org) &Medical Educational web (www.meduweb.com)
Not to be reproduced without permission of Vascular Society of Egypt
|04-05-2010, 08:04 PM||post no: 2|
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