Polyposis & Cancer Colon

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Page 1: Polyposis & Cancer Colon

الرحمن الله بسمالرحيم


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Colorectal polyps• Polyp is a clinical term that describes any projection from

the surface of the intestinal mucosa regardless of its histologic nature.

• Colorectal polyps may be classified as A) Neoplastic (tubular adenoma, villous adenoma, tubulovillous

adenomas).B) Hamartomatous (juvenile, Peutz-Jeghers, Cronkite-Canada

and Cowden). C) Inflammatory (pseudopolyps and benign lymphoid polyp) D) Hyperplastic.

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Polyps of the Colon & RectumColorectal polyps are masses of tissue that project into the

lumen. sessile or pedunculated, benign or malignant, mucosal, submucosal, or muscular lesions.

"Polyp" is a morphologic term, and no histologic diagnosis is implied.

Polyposis is a term reserved for the presence of many polyps in the large bowel.

Estimates of the incidence of colonic and rectal polyps in the general population range from 9% to 60%.

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Polyps of the Colon & Rectum

• Approximately 50% of polyps occur in the sigmoid or rectum.

• About 50% of patients with adenoma have more than one lesion, and 15% have more than two lesions.

• Approximately 25% of patients who have five or more adenomatous polyps have a synchronous colon cancer at the initial colonoscopy.

• An increased incidence of adenomas in breast cancer patients has been reported.

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Polyps of the Colon & Rectum

• Approximately 50% of polyps occur in the sigmoid or rectum.

• About 50% of patients with adenoma have more than one lesion, and 15% have more than two lesions.

• Approximately 25% of patients who have five or more adenomatous polyps have a synchronous colon cancer at the initial colonoscopy.

• An increased incidence of adenomas in breast cancer patients has been reported.

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Polyps of the Large Intestine.Type Histologic Diagnosis

Neoplastic •Adenoma1. Tubular adenoma (adenomatous

polyp) 75-80%.2. Tubulovillous adenoma

(villoglandular adenoma) 8-15%.3. Villous adenoma (villous papilloma)


Hamartomas •Juvenile polyp•Peutz-Jeghers polyp

Inflammatory Inflammatory polyp (pseudopolyp)Benign lymphoid polyp

HyperplasticMiscellaneous Lipoma, leiomyoma, carcinoid

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Neoplastic PolypsAdenomatous polyps are common, occurring in up to 25% of the population older

than 50 years of age. By definition, these lesions are dysplastic. Invasive carcinoma is present in 5% of all adenomas, but the incidence correlates

with the size and type of the adenomaTubular adenomas are associated with malignancy in only 5% of cases, whereas

villous adenomas may harbor cancer in up to 40%. Tubulovillous adenomas are at intermediate risk (22%).

Invasive carcinomas are rare in polyps smaller than 1 cm; the incidence increases with size. The risk of carcinoma in a polyp larger than 2 cm is 35 to 50%.

Although most neoplastic polyps do not evolve to cancer, most colorectal cancers originate as a polyp.

It is this fact that forms the basis for secondary prevention strategies to eliminate colorectal cancer by targeting the neoplastic polyp for removal before malignancy develops.

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Type Histologic features Incidence (%) Invasive malignancy (%)

Adenomatous (tabular adenoma)

Branching tubules embedded in lamina propria

75 5

Villous (villous adenoma)

Finger-like projections of epithelium over lamina propria

10 40

Intermediate (tubulovillous adenoma)

Mixture of adenomatous and villous patterns

15 22

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Colorectal polyps

• Hamartomatous Polyps (Juvenile Polyps):– Juvenile polyps: are not usually premalignant. These

lesions are the characteristic polyps of childhood but may occur at any age. The polyps are pedunculated, usually single or few in number. Commonly affecting the rectum. Bleeding is a common symptom and intussusception and/or obstruction may occur. Because the gross appearance of these polyps is identical to adenomatous polyps, these lesions should also be treated by polypectomy.

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Colorectal polyps• Hamartomatous Polyps (Juvenile Polyps):– Peutz-Jeghers syndrome is characterized by polyposis of the

small intestine, and to a lesser extent, polyposis of the colon and rectum. Characteristic melanin spots are often noted on the buccal mucosa and lips of these patients. The polyps of Peutz-Jeghers syndrome are generally considered to be hamartomas and are not thought to be at significant risk for malignant degeneration. However, carcinoma may occasionally develop. Because the entire length of the gastrointestinal tract may be affected, surgery is reserved for symptoms such as obstruction or bleeding or for patients in whom polyps develop adenomatous features.

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Colorectal polyps• FAMILIAL ADENOMATOUS POLYPOSIS ( FAP)(Familial Polyposis Coli,

FPC)– Aetiology:

• This rare autosomal dominant condition.• Clinically, patients develop hundreds to thousands of adenomatous polyps shortly

after puberty. The lifetime risk of colorectal cancer in FAP patients approaches 100% by age 50 years.

– Pathology:• Polyps usually start to appear at puberty, affecting the sigmoid colon and rectum

initially and by the age of 20 years the entire colon and rectum are affected by immense numbers of polyps ( at least 100), ranging from 1 mm to several cms.

• Polyps may be sessile or pedunculated.• Three histological types are recognized; the tubular, tubulo-villous, and villous.• Left untreated, carcinoma develops in 100% of the affected patients by the fifth


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Colorectal polyps

• Clinical picture:– The disease usually manifests itself soon after puberty by

attacks of lower abdominal pain, diarrhoea, tenesmus with the passage of blood and mucus in the stools. Loss of weight, anaemia and general debility are common.

– Rectal examination reveals the adenomas.• Investigations:– Barium enema shows multiple rounded filling defects

throughout the colon and the rectum.– Sigmoidoscopy or colonoscopy and biopsy prove the nature

of the disease.

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Macroscopic appearance of the colon in classical familial adenomatous polyposis. The specimen shows dense carpeting of

the colonic mucosa with thousands of adenomas.

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Colorectal polyps

• Treatment:– Once the diagnosis of FAP has been made and polyps are

developing, treatment is surgical. – Three operative procedures (options) can be considered:

1. total proctocolectomy: with either an end ileostomy or continent (Kock's) ileostomy

2. Restorative proctocolectomy : with ileal pouch–anal anastomosis with or without a temporary ileostomy

3. Total abdominal colectomy with ileorectal anastomosis; the rectum is preserved, and polypi in the rectum are followed endoscopically and removed periodically.

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Carcinoma of the colon• Incidence: Colorectal carcinoma is the most common malignancy of the gastrointestinal

tract. The incidence is similar in men and women.

• Risk Factors:(1) Aging: Aging is the most important risk factor for colorectal cancer, with incidence rising steadily

after the age of 50 years. More than 90% of cases diagnosed are in people older than age 50 years.

(2) Hereditary Risk Factors: Approximately 80% of colorectal cancers occur sporadically, while 20% arise in patients with a known family history of colorectal cancer.

(3) Environmental and Dietary Factors: Colorectal carcinoma occurs more commonly in populations that consume diets high in animal fat and low in fiber.

(4) Inflammatory bowel disease: Patients with long-standing ulcerative colitis are at increased risk for the development of colorectal cancer. Crohn's pancolitis have similar risk.

(5) Other Risk Factors:Cigarette smoking reportedly increases the risk of colorectal cancer . Patients with ureterosigmoidostomy are also at increased risk . Also in women, gallstones (and the consequent cholecystectomy) are associated with colorectal cancer,

especially in the right colon.

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Risk Factors Associated with Colon CancerRisk Factor Comment

Geographic variation Highest risk in Western countries and lowest risk in developing countries

Age Risk increase sharply after the fifth decade

Diet Increased with total and animal fat diets

Physical inactivity Increased with obesity and sedentary life style

Adenoma Risk dependent on type and size

FAP penetrance in gene carriers 100%

HNPCC penetrance in gene carriers 80%

Hamartomatous syndromes Risk increased with Peutz-Jeghers syndrome and juvenile polyposis but not isolated juvenile polyps

Previous history of colon cancer Increased risk for recurrent cancer

Ulcerative colitis 10–20% after 20 years

Radiation Associated with a mucinous histology and poor prognosis

Ureterosigmoidostomy 100–500 times increased risk at or adjacent to the uretero-colonic anastomosis

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Carcinoma of the colon

• Pathology:– Site:

• The sigmoid colon is the commonest site (50%) probably because its contents are solid, stagnant and irritant, and it is often the seat of precancerous lesions (i.e., FAP and UC)

• Caecum and ascending colon: 25%• Transverse colon: 20%.• Descending colon: 5%.• Multiple synchronous colonic cancers (i.e., two or more

carcinomas occurring simultaneously) are found in 5% of patients. Metachronous cancer is a new primary lesion in a patient who has had a previous resection for cancer.

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Carcinoma of the colon• Gross picture:– Cauliflower growth: This occurs in the right colon.– Scirrhous growth (annular and tubular): This occurs in the

left colon.– Malignant ulcer: This occurs commonly in the caecum.

• Microscopic picture– Histologically the tumour is an adenocarcinoma that arises

from the columnar epithelium. It may be well, moderately, or poorly diff erentiated.

– Some tumours have a colloid structure, occur in younger patients, and have a poor prognosis.

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Carcinoma of the colon• Spread:

– Direct spread:• Carcinoma grows circumferentially and may completely encircle the bowel

before it is diagnosed; this is especially true in the left colon, which has a smaller caliber than the right. It takes about 1 year for a tumor to encircle three-fourths of the circumference of the bowel.

• Longitudinal submucosal extension occurs with invasion of the intramural lymphatic network, but it rarely goes beyond 2 cm from the edge of the tumor unless there is concomitant spread to lymph nodes.

• As the lesion extends radially, it penetrates the outer layers of the bowel wall, and it may invade adjacent structures: the liver, the greater curvature of the stomach, the duodenum, the small bowel, the pancreas, the spleen, the bladder, the vagina, the kidneys and ureters, and the abdominal wall. Subacute perforation with inflammatory attachment of bowel to an adjacent viscous may be indistinguishable from actual invasion on gross examination.

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Carcinoma of the colon• Lymphatic spread:

– Cancer spreads from the colon to the following lymph node groups, in sequence:1. Epicolic nodes on the bowel wall.2. Paracolic nodes between the marginal artery and the bowel.3. Intermediate nodes on the main vessels.4. Principal nodes alongside the superior and inferior mesenteric vessels.

– From the principal nodes further spread occurs to the parpa-aortic lymph nodes, then to cysterna chyli and thoracic duct. The left supraclavicular lymph nodes may be involved by retrograde flow from the thoracic duct (Virchow’s glands) giving positive Troisier’s sign.

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Carcinoma of the colon

• Blood spread:– Venous invasion may allow tumor cells be carried via

the portal venous system to the liver. Tumor embolization also occurs through lumbar and vertebral veins to the lungs and elsewhere. Metastases to ovaries are mostly hematogenous; they are found in 1–10% of women with colorectal cancer. An attempt is made to avoid producing hematogenous metastases during operation by minimizing manipulation of the tumor prior to ligation of the blood supply.

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Carcinoma of the colon• Transperitoneal spread:– "Seeding" may occur when the tumor has extended through the

serosa and tumor cells enter the peritoneal cavity, producing local implants or generalized abdominal carcinomatosis. Large metastatic deposits in the pelvic cul-de-sac are palpable as a hard shelf (Blumer's shelf).

• Intraluminal spread:– Malignant cells shed from the surface of the tumor can be swept

with the fecal current. Implantation more distally on intact mucosa occurs rarely, if ever, but viable exfoliated cells presumably can be trapped in an anastomotic suture or staple line during operation.

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Carcinoma of the colon• Complications:

1. Intestinal obstruction: 1. chronic obstruction is common especially in left colon cancer (20%). This

tendency is attributed to:1. The smaller lumen of the left colon.2. Stool tends to be more solid.3. Carcinoma tends to be of the stenosing type.

2. Acute obstruction may occur due to faecal impaction or intussusception (in carcinoma at the ileocaecal valve and sigmoid colon).

2. Haemorrhage: Chronic bleeding is the rule and causes iron deficiency anaemia. Massive bleeding is rare.

3. Perforation: is rare and is usually gradual with the formation of a pericolic abscess and faecal fistula.

4. Malignant ascites: results from liver secondaries, lymph nodes compressing the portal vein and Transperitoneal spread.

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Carcinoma of the colon

• Staging:– Colorectal cancer staging is based upon tumor depth and

the presence or absence of nodal or distant metastases. – Old staging systems, such as the Dukes' Classification and

its Astler-Coller modification, have been largely replaced by the TNM staging system (Table=).

– The preoperative evaluation usually identifies stage IV disease. In colon cancer, differentiating stages I, II, and III depends upon examination of the resected specimen. In rectal cancer, endorectal ultrasound may predict the stage .

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Carcinoma of the colon• Tumor Stage (T) Definition

– Tx Cannot be assessed– T0 No evidence of cancer– Tis Carcinoma in situ– T1 Tumor invades submucosa– T2 Tumor invades muscularis propria– T3 Tumor invades through muscularis propria into subserosa or into nonperitonealized pericolic tissues– T4 Tumor directly invades other organs or tissues or perforates the visceral peritoneum of specimen

• Nodal Stage (N) – NX Regional lymph nodes cannot be assessed– N0 No lymph node metastasis– N1 Metastasis to one to three pericolic or perirectal lymph nodes– N2 Metastasis to four or more pericolic or perirectal lymph nodes– N3 Metastasis to any lymph node along a major named vascular trunk

• Distant Metastasis (M) – MX Presence of distant metastasis cannot be assessed– M0 No distant metastasis– M1 Distant metastasis present

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Stage Grouping


0 Tis N0 M0 I T1 N0 M0 A T2 N0 M0 A

IIA T3 N0 M0 BIIB T4 N0 M0 BIIIA T1-T2 N1 M0 CIIIB T3-T4 N1 M0 CIIIC Any T N2 M0 CIV Any T Any N M1

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TNM Staging of Colorectal Carcinoma and 5-Year Survival

Stage TNM 5-Year Survival

I T1-2, N0, M0 70–95%

II T3-4, N0, M0 54–65%

III Tany, N1-3, M0 39–60%

IV Tany, Nany, M1 0–16%

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Carcinoma of the colon

• Clinical features:– Right colon cancer is more common in females,

while left colon cancer is more common in males. • Clinical features depend upon the location of

the tumour, its size, and the presence of metastases.

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Rigid Sigmoidoscopy

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Carcinoma of the colon• A. Right colon cancer:• (Irritative manifestations)

– The usual presentation is vague with anaemia, weakness and loss of weight (Anaemia, Anorexia and Asthenia).

– The patient may present with recurrent attacks of pain in the right iliac fossa.– A hard mass may be present in the right side of the abdomen. It is

differentiated from appendicular mass by the long duration and absence of toxaemia and tenderness. A malignant mass is hard, ill-defined, irregular and fixed.

– The patient does not present by intestinal obstruction as • The lesion is usually of the cauliflower vari ety.• The contents are liquid.• The lumen of the colon is wide.

– Obstruction occurs, rarely, if the lesion obstructs the ileocaecal valve.

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Carcinoma of the colon• B. Left colon cancer:• (Obstructive manifestations)

1. The usual presentation is change of bowel habits, usually as progressive constipation, but there may be diarrhoea or attacks of constipation alternating with diarrhoea. These patients are usually diag nosed and treated as having colitis. Spurious diarrhoea (early morning slime) may be present.

2. Large bowel obstruction: The patient may present as acute, subacute or chronic large bowel ob struction. There is constipation, severe abdominal distension but vomiting is late. Carcinoma of the sigmoid colon is a common cause of intestinal obstruction in an elderly patient.

3. Bleeding per rectum: Carcinoma of the left colon is a common cause of fresh bleeding per rectum but it is not a common cause of massive bleeding (compare with diverticular disease and angiodysplasia).

4. Mass in the left side of abdomen: As the lesion is usually of the infiltrating scirrhous type, it rarely presents by a mass. If a mass is palpable, it is usually due to faecal impaction above the tumour.

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Carcinoma of the colon• Investigations

1. Blood picture may reveal microcytic hypochromic anaemia. Sigmoidoscopy is essential in all patients with altered bowel habit or rectal bleeding. Biopsy is obtained from suspicious le sions. Total colonoscopy is important to exclude a second higher tumour.

2. Sigmoidoscopy is essential in all patients with altered bowel habit or rectal bleeding. Biopsy is obtained from suspicious le sions. Total colonoscopy is important to exclude a second higher tumour.

3. Barium enema. The tumour appears as a fixed irregular stricture or filling de fect. Annular strictures of the left colon show a characteristic "apple core appearance". Even with a palpable rectal cancer, contrast radiography is useful to exclude a second higher tumour.

4. To detect spread liver function tests, abdominal ultrasound (or CT scan), and chest X-ray are done. If the tumour is expected to be close to the ureter, an intravenous urogram (IVU) is essential.

5. Carcinoembryonic antigen (CEA) is a tumour marker whose se rum level is high in colorectal cancer but is not specific. It is of prognostic rather than diagnostic value. The level drops after a successful radical surgery. If it shows a rise in the follow up period, this signifies recurrence.

6. For patients presenting with acute intestinal obstruction plain X-ray of the abdomen, blood picture and electrolytes are needed .

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Apple core appearance

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A double-contrast barium enema showing a carcinoma in the sigmoid colon (The classic apple core defect) .

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Carcinoma of the colon• Treatment• General principles

– Surgery is the main line of treatment. Radical resection is the only curative measure. For inoperable tumours resection also offers the best palliation.

– Treatment depends on whether the tumour presents by acute obstruction or not and whether the tumour is operable or not.

– Criteria of inoperability 1. Unfit patient.2. Unresectable liver metastases.3. Para-aortic lymph node involvement.4. Peritoneal nodules5. Irresectable primary tumour.

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Carcinoma of the colon

• A. Treatment of colon cancer without acute intestinal obstruction:– Operable cases: elective radical resection. The operation

aims at cure and entails removal of the tumour bearing segment together with its lymphatic drain age area, in one mass; and then to restore bowel continuity. Since the lymph nodes are so close to the main blood vessels arising from the superior and inferior mesenteric, their clearance requires ligation and division of these vessels at their origin, and conse quently the whole part of the colon supplied by the removed ves sels should be resected.

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Polyp Snaring

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Principles of Surgical Management of Colo-rectal Ca

As a basic principle, any colorectal cancer is an indication for surgery unless widespread tumor dissemination or general contraindications from the patient's overall health status are present.

The general goal for surgical management is either to achieve cure from the tumor and extension of survival or disease-free survival

Local tumor control generally is the primary treatment objective to prevent local tumor complications, i.e., obstruction, perforation, bleeding, and pain. Even in the presence of distant metastases in the liver or lung, resection of the primary tumor remains a reasonable priority.

Since solitary or a limited number of metastases in the liver or lung often may be treated surgically by partial organ resection or metastasectomy with a cure rate of up to 35%, their presence should not necessarily alter the surgical approach at the primary site to do a curative resection.

In contrast to rectal cancer, neoadjuvant treatment (i.e., preoperative chemoradiation) is not indicated in the overwhelming majority of colonic cases unless a locally very advanced lesion is treated with chemotherapy in anticipation of an otherwise unresectable mass. Adjuvant (i.e., postoperative) treatment will be discussed in a later section.

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Preparation for SurgeryTransfusion: Even though many colonic operations can be performed without a blood

transfusion, it is recommended to have the patient's blood typed and crossed-matched, with a minimum of 2 units of blood available at the beginning of the surgery.

Bowel Cleansing: the products used generally are based on either polyethylene glycol (e.g., GoLytely) or sodium phosphate (Fleet Phospho-soda), the latter of which is contraindicated in patients with renal failure.

Antibiotic Prophylaxis: Intravenous broad-spectrum antibiotics often contain a combination of intravenous second- or third-generation cephalosporin (cefoxitin or ceftriaxone) with metronidazole.

Thromboembolic ProphylaxisUrinary Catheters/StentsNasogastric Tube: is not necessary on a routine basis for patients undergoing resection

of the colon or rectum unless they present with a complete or partial bowel obstruction.166

Preoperative Marking of Ostomy Site

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Carcinoma of the colona) Tumours of the caecum or the ascending colon: require a right hemicolectomy: The terminal 10 inches of the ileum, the caecum, the ascending colon, the hepatic flexure, and the right

third of the transverse colon (to the right of the middle colic vessels) are resected. The operation is completed by performing an ileotransverse anastomosis.

b) Tumours of the hepatic flexure: are treated by extended right hemicolectomy, where in addition to the above, the middle colic vessels are included. The resection extends to the junction of the right two thirds and the left third of the transverse colon.

c) Tumours of the transverse colon: are treated by transverse colectomy where the middle colic vessels are divided flush at their origin and the transverse colon is resected with the hepatic and splenic flexures, the transverse mesocolon and the omentum A colocolonic anastomosis is then performed.

d) Tumours of the splenic flexure or the descending colon: are treated by left hemicolectomy: the resection includes the left half of the transverse colon (to the left of the middle colic vessels), the splenic flexure and descending colon .

e) Tumours of the distal transverse colon and splenic flexure: are treated by extended left hemicolectomy, where the left hemicolectomy is extended proximally to include the right branches of the middle colic vessels.

g) Tumours arising in a long redundant sigmoid colon may be treated by sigmoid colectomy, where the sigmoid vessels are divided at their origin from the inferior mesenteric artery and the resection includes the sigmoid colon and mesocolon and sigmoid vessels.

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Carcinoma of the colonExtent of resection for carcinoma of the colon. A. Caecal and right colonic

cancer. B. Hepatic flexure cancer. C. Transverse colon cancer. D. Splenic flexure cancer.

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Carcinoma of the colonExtent of resection for carcinoma of the colon . E. Descending

colon cancer. F. Sigmoid colon cancer.

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Carcinoma of the colon– Palliative operations for Inoperable cases : (whether

inoperability is diagnosed before or during operation)• Whenever possible, palliative resection of the colon cancer is

preferred. Here there is no need for wide resection of the bowel nor its lymphatics and vessels. The operation is destined to obviate the risk of obstruction and bleeding.

• Tumours of the right colon require a side to side ileo-transverse anastomosis.

• Tumours elsewhere in the colon require a proximal colostomy.

– After palliative surgery, radiotherapy, chemotherapy (5-flurouracil) and immunotherapy may be given to the patient.

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Carcinoma of the colon• B. Treatment of colon cancer with acute intestinal obstruction:

– Urgent surgery is required after adequate resuscitation. – The best is colon resection (radical or palliative depending on operability).– If the lesion is in the right colon, primary resection anastomosis is feasible .If the

tumour is in the left colon, the proximal end of the colon is brought to the surface as end colostomy. The distal end is either closed as a Hartmann s pouch or brought to the surface as a mucous fistula.

– N>B: Nowadays obstructed left colon cancer can be treated by resection and primary anastomosis because it has a better prognosis as it allows earlier removal of the tumour. The proximal colon should be decompressed and cleaned by on-table lavage before anastomosis is done.

– Irresectable tumours of the right colon are treated by ileotransverse anastomosis. Irresectable tumours of the left colon are treated by palliative transverse or pelvic colostomy.

– For the critically ill, a proximal colostomy is all that can be done. After relief of obstruction, most colonic carcinomas can be resected at a second-look operation.

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