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The Colon

  1. Colon is mainly concerned with absorption of water and electrolytes and to a lesser extent with reabsorption of bile acids.
  2. The more distal colon arises from the embryonal hindgut and is supplied by the inferior mesenteric artery; it has less absorptive capacity and - with the rectum - functions mainly as a storage site for faeces prior to evacuation.
  3. The colon and rectum are, together, a little over 1m in length, and the diameter diminishes from caecum to sigmoid, increasing again in the rectum. Most of the outer longitudinal muscle coat is gathered into 3 distinct bands - the taeniae coli - 6 to 10mm in width.
  4.  These run from the tip of the caecum to the rectum, where they merge to form a more continuous covering. The taeniae are shorter then the colon and therefore gather' it into sacculations, or haustra.
  5. The mucosa of the colon is thrown into folds, the plicae semilunares, which take on a triangular appearance in the transverse colon.
  6. Unlike the small intestine, the colon is relatively fixed, particularly the ascending and descending segments. The more mobile transverse colon has a short mesentery, whilst the sigmoid, with a broader, longer mesentery is generally the most mobile.
  7. Covering the serosal surface of the colon are fatty structures arising within the mesentery known as the appendices epiploicae.
  1. Sigmoid and caecal volvulus
    1. Volvulus = rotation of the gut on its own mesenteric axis
    2. Produces partial or complete intestinal obstruction
    3. Blood supply compromised resulting in intestinal ischaemia
    4. Venous congestion leading to infarction can occur
    5. Arterial supply rarely compromised
    6. Long narrow based mesentery predisposes to volvulus
  • Sigmoid volvulus
  1. Sigmoid is commonest site of colonic volvulus followed by caecum then splenic flexure. 
  2. Anticlock wise rotation of bowel.
  3. Usually seen in elderly or those with psychiatric disorders
  4. More common in Asian population
  5. >Incidence is 10 times higher than in Europe or USA
  6. Torsion is usually anti clock wise form 180 – 540O
  1. Clinical features
    1. Large bowel obstruction – pain, constipation and vomiting
    2. Disproportionate abdominal distension
    3. 50% patients have had a previous episode
    4. Severe pain and tenderness suggests ischemia
    5. Plain abdominal x-ray may show a large ‘bean’ shaped loop of large bowel arising from pelvis
    6. Most common sign & symptom are abdominal pain, asymmetric distention & absolute constipation
    7. Plain abdominal radiograph are usually diagnostic, contras barium enema usually adequate when, diagnosis is in doubt, bird break appearance is characteristic.
    8. Sign on CT-scan whirl sign
    9. Dilated loop usually lie in the right side.
    10. If diagnostic doubt consider a water soluble contrast enema will demonstrate site of obstruction
  2. Management
    1. Resuscitation with intravenous fluids is essential
    2. Conservative management can be attempted if so clinical features of ischaemia
    3. Rigid Sigmoidoscopy can be both diagnostic and therapeutic. Derotation of bowel performed.
    4. Elective sigmoid colectomy performed.
    5. Obstruction usually at 15 cm which when advanced passed produces release of flatus
    6. Flatus tube can be inserted and left for 2-3 days
    7. 80% of patients will settle with conservative management
    8. If decompression occurs no emergency treatment required
    9. 50% further episode of volvulus within 2 years
    10. If decompression fails or features of peritonitis
      Options are:
      1. Sigmoid colectomy and primary anastomosis
      2. Hartmann’s procedure
      3. Paul Mickulicz Colostomy
      4. Sigmoidopexy best avoided
Treatment of Large Bowel Obstruction
Site of Obstruction Procedure
Right-sided colonic obstruction
(cancer or volvulus)
· Resection with ileo-transverse anastomosis
Cancer of sigmoid colon · Hartmann's operation (sigmoidectomy with descending colostomy and closure of the rectal stump),
· Sigmoidectomy with primary colorectal anastomosis
· Abdominal colectomy with ileorectal anastomosis''.
Cancer of distal or mid rectum · Loop colostomy or defunctioning colostomy (to relieve obstruction)
followed by neoadjuvant chemoradiation'', (with the plan to resect the primary lesion at a later time)
  • Caecal volvulus
  1. Incidence is less than that of sigmoid volvulus
  2. Accounts for about 25% cases of colonic volvulus
  3. Incomplete midgut rotation is a predisposing factor
  4. Results in inadequate fixation of caecum to posterior abdominal wall
  5. Volvulus usually occurs clockwise around ileocolic vessels
  6. Usually also involves terminal ileum and ascending colon
  7. Most common distal colonic lesion associated with caecale volvulus is colonic carcinoma & diverticulitis.
  1. Clinical features
    1. Presents with clinical features of proximal large bowel obstruction
    2. Colicky abdominal pain and vomiting are common
    3. Abdominal distension may occur
    4. Plain abdominal x-ray shows a comma shaped caecal shadow in mid abdomen
    5. Small bowel loops may lie to the right of the caecum
    6. If diagnostic doubt consider a water soluble contrast enema will show beaked appearance in ascending colon
  2. Management
    1. Exploratory Laparotomy & derotation of bowel is treatment of choice.
    2. Elective right hemicolectomy performed.
    3. If colon is ischaemic then right hemicolectomy & temprory ileostomy should be performed
  1. Colonic Obstruction
    1. Large bowel obstruction may be caused by neoplasms or anatomic abnormalities such as volvulus, incarcerated hernia, stricture, or obstipation.
    2. Large bowel obstruction from an anatomic abnormality leads to colonic distention, pain, anorexia, and, late in the course, feculent vomiting. Distinguishing colonic ileus from organic obstruction is important.
  1. Imaging Studies:
    1. Flat and upright abdominal roentgenography demonstrates dilation of the small and/or large bowel and air fluid levels.
    2. Tracing colonic air around the colon, into the left gutter, and down into the rectum or demonstrating an abrupt cut-off in colonic air suggests the anatomic location of the obstruction.
    3. A dilated colon without air in the rectum is more consistent with obstruction. The presence of air in the rectum is consistent with obstipation, ileus, or partial obstruction.
    4. The characteristic bird's beak of volvulus may be seen.
    5. Flexible endoscopy preceded by rectal enema may be useful in evaluating left-sided colonic obstruction.
  2. Procedures:
    1. Endoscopic reduction of volvulus
    2. Barium enema for reduction of intussusception
    3. Cleansing enemas
  3. Surgical Care:
    1. Surgical care is directed at relieving the obstruction.
    2. In most patients, the obstructing lesion is resected.
      1. Because the colon has not been cleansed, anastomosis often is risky.
      2. After resection, most surgeons perform a proximal colostomy if the obstruction is on the left side or ileostomy if it is on the right side.
    3. In patients with substantial comorbidity and surgical risk or in the presence of an unresectable tumor, a diverting proximal colostomy or ileostomy may be performed without resection.
  1. Ischaemic Colitis
    1. Ischaemic colitis arises from a failure of the blood supply to the colon and occurs most commonly in conjunction with advanced atherosclerotic disease affecting at least two of the major branches of the aorta.
    2. Acute occlusion of a major artery leads to a surgical emergency with colonic gangrene or to a less acute syndrome typified by abdominal pain and bloody diarrhoea.
    3. Arterial emboli, dissecting aortic aneurysm, and vasculitic cases may also be responsible.
    4. The most vulnerable areas of the colon are around the splenic flexure, and, to a lesser extent, the rectosigmoid region, both of which lie in relatively poorly vascularized
    5. The plain abdominal radiograph may show thumbprinting', representing oedema of the mucosal folds. Contrast radiology shows swollen mucosal folds, sawtooth irregularities and narrowing.
    6. In acute ischaemia, the involved section of bowel undergoes infarction; it is dilated and darkly congested with a friable wall, and is usually filled with blood.
    7.  Mucosal ulceration and intense submucosal oedema with haemorrhage and necrosis are seen. Granulation tissue is later replaced by fibrosis which may lead to post-ischaemic stricturing.In chronic ischaemia, it is common to find a stricture together with ulceration and granulation tissue. Fibrosis of the submucosa and circular muscle coat is also characteristic.
    8. Where mucosa survives, iron-laden macrophages are often prominent in the lamina propria.
  2. Diverticular Disease
    1. Diverticula are acquired pouches of mucosa and submucosa herniating through the muscular layers of the bowel.
    2. It may be congenital or acquired, Acquired more common than congenital. 
    3. Most common site sigmoid colon.
    4. Most common site at antimesentric border.
    5. Colonic diverticula is pseudo diverticula.
    6. They are commoner with ageing and in populations where typical diets are low in fibre content. The sigmoid is affected in 95% but diverticula may occur throughout the colon.
    7. They usually arise in rows between the lateral and mesenteric taenii at the site of (potential) weakness in the bowel wall, where large blood vessels penetrate the interfascicular connective tissue of the circular muscle layer.
    8. Haemorrhage from a diverticulum in the absence of inflammation may be responsible for brisk and usually self-limiting rectal bleeding.
    9.  As diverticulosis is usually accompanied by marked thickening of the circular muscle layer of the colon, barium studies show shortening and narrowing of the sigmoid segment as well as of the diverticula, Sawtooth app.
    10. Flexible sigmoidoscopy and/or colonoscopy is indicated to help with the diagnosis.
    11. A small minority of patients with diverticulosis develop diverticulitis. This results when an inflamed diverticulum becomes, effectively, an abscess, generally with subsequent perforation and localized peritonitis. Lower abdominal pain and tenderness with fever and leucocytosis are usual.
    12. Colonic diverticulae are outpouchings of colonic wall
    13. Usually result from herniation of mucosa through muscular wall
    14. Occur at sites where mesenteric vessels penetrate the bowel wall
    15. Increased prevalence with age
    16. 10% population at 40 years
    17. 60% population at 80 years
    18. More common in developed countries
    19. Diverticulitis may be complicated by free perforation and generalized faecal peritonitis, fistula formation (typically to the gynaecological organs or the bladder, but occasionally to the pelvic floor), intra-abdominal abscess, or haemorrhage. Symptoms vary according to the nature of the fistula, but pneumaturia, recurrent urinary tract infection, or passage of faeces from the vagina will often be more indicative than routine investigations.
    20. The typical pathology of diverticular disease includes a narrowed length of sigmoid colon with thickened bands of circular muscle, giving the bowel a concertina-like appearance.
    21. Most common symptom of diverticulitis is abdominal Pain.
      1. Investigation of choice – for diverticuloses is Barium Enema (Saw tooth like image)
  1. Investigation of choice – for diverticulitis CT-Scan.
  2. Sigmoidoscopy / Colonoscopy contraindicated in diverticulitis.
  • Treatment
  1. Bowel rest by restricting oral intake and intravenous fluids
  2. Intravenous antibiotics - 2nd generation cephalosporin (e.g. cefuroxime) and metronidazole
  3. Active observation for the development of complications
  4. If abscess formation - percutaneous drainage under radiological guidance usually possible
  5. Subsequent elective resection and primary anastomosis often required
  • Indication of operation in diverticulitis.
    1. At least two documented attack
    2. Failure of medical therapy
    3. Complicated diverticulitis
    4. For recurrent or persistent hemorrhage.
    5. Diverticuloses occurring in young < 40 yrs as in young the disease follow aggressive course.
  1. Colonic pseudo-obstruction
    1. Often also referred to as Olgilvie's syndrome
    2. A condition characterised by reduced colonic mobility and dilatation
    3. Presents with symptoms and signs of large bowel obstruction
    4. Excludes obstruction lesion
    5. Proximal colon is the most common site.
    6. Often precipitated by other medical or surgical conditions including :-
      1. Chest infection
      2. Myocardial infarction
      3. Cerebrovascular accident
      4. Renal failure Puerperium
      5. Abdominal malignancy
      6. Orthopaedic trauma
      7. Myxoedema
      8. Electrolyte disturbances
  • Management
  1. Conservative treatment is the option of choice.
  2. Remove precipitating causes
  3. Stop anticholinergics drugs/ Reduce the use of opiates/ Correct electrolyte disturbances/ Decompress colon with Flexible sigmoidoscopy or flatus tube
    1. The cautious use of enemas
    2. Intravenous neostigmine
    3. Consider surgery if failure of conservative management or if cecal diametric >12 cm
  1. Lower gastrointestinal haemorrhage
    1. Accounts for 20% cases of acute gastrointestinal haemorrhage
    2. Most patients are elderly
    3. Most cases settle spontaneously without the need for emergency surgery
    4. Following investigation often a cause is not found
  • Causes
  1. Diverticular disease
  2. Angiodysplasia
  3. Inflammatory bowel disease
  4. Ischaemic colitis
  5. Infective colitis
  6. Colorectal carcinoma
  1. Angiodysplasia
    1. Acquired malformation of intestinal blood vessels
    2. 80% lesions occur in the right side of the colon
    3. Often associated with cardiac valvular disease
    4. Dilated vessels or 'cherry red' areas may be seen at colonoscopy
    5. Early filling of vessels seen at angiography
    6. Bleeding may be visible during capillary phase of angiogram
    7. Angiodysplasia is an incidental finding during 5% of colonoscopies
    8. Seen in up to 25% of asymptomatic patients over the age of 75 years
  • Investigation
  1. Most patients are stable and can be investigated once bleeding has stopped
  2. In the actively bleeding patient consider:
  3. Colonoscopy - can be difficult
  4. Selective mesenteric angiography
  5. Radionuclide scanning
  6. Uses technetium-99m labeled red blood cells
  7. Most sensitive investigation radiolabelled red cell scan.
Rate of bleeding for detection
Investigation Rate of bleeding (ml/min)
Radiolabel red cell scan 0.1
Mesenteric angiography 1.0
Non-selective aortic angiography 6.0
Colonoscopy Any
Intraoperative endoscopy Any
  • Management
  1. Acute bleeding tends to be self limiting
  2. Consider selective mesenteric embolisation if life threatening haemorrhage
  3. If bleeding persists perform endoscopy to exclude upper GI cause
  4. Proceed to laparotomy and consider on-table lavage an panendoscopy
  5. If right-sided angiodysplasia perform a right hemicolectomy
  6. If bleeding diverticular disease perform a sigmoid colectomy
  7. If source of colonic bleeding unclear perform a subtotal colectomy and end-ileostomy
  1. Inflammatory bowel disease
    1. Causes of colonic inflammation
      1. Infection - bacteria, viruses, parasites
      2. Ulcerative colitis
      3. Crohn's' disease
      4. Radiation enteritis
      5. Ischaemic colitis
      6. Microscopic colitis
      7. Drug-induced colitis
    2. Ulcerative colitis
      1. Peak age of onset 20 - 35 yrs
      2. Characteristic feature - acute mucosal inflammation with crypt abscesses
    3. Crohn’s disease
      1. Characteristic feature - patchy transmural inflammation with non-caeseating granuloma
    4. Pathophysiology
      1. Increased incidence in first degree relatives
      2. Increased concordance in monozygotic twins
Ulcerative colitis Crohn's disease
Lesions continuous – Mucosa and sub mucosa Lesions patchy – full thickness
Rectum always involved (Most common site) Rectum normal in 50%
Terminal ileum involved in 10% Terminal ileum involved in 30% (Most common site)
Granulated ulcerated mucosa Discretely ulcerated mucosa
No fissuring Cobblestone appearance with fissuring
Pseudo polyp present No
Disease confined to colorectal area only Any site from oral cavity to anal canal.
Normal serosa Serositis common
Muscular shortening of colon Fibrous shortening
Fibrous strictures rare Strictures common
Fistulae rare Enterocutaenous or intestinal fistulae in 10%
Anal lesions in <20% Anal lesions in 75%
  Anal fistulae & chronic fissures
Malignant change well recognised Possible malignant change
Barium anema – lead pipe Barium meal – String sign of Kantoor
Features of malignant structure
Three important features are suggestive of malignant strictures:
  1. Appearance later in the course of ulcerative colitis (60% after 20 years versus 0% before 10 years)
  2. Location proximal to the splenic flexure (86% malignant)
  3. Large bowel obstruction caused by the stricture.
  • Clinical features of inflammatory bowel disease
  1. Ulcerative colitis
    1. 30% disease confined to rectum
    2. 15% develop more extensive disease over 10 years
    3. 20% total colonic involvement from onset
    4. Patients generally fall into following categories:
  • Severe acute colitis                    
  • Intermittent relapsing colitis
  • Chronic persistent colitis                           
  • Asymptomatic disease
  1. Assessment of disease severity
    1. Mild = < 4 stools per day.  Systemically well
    2. Moderate = > 4 stools per day.  Systemically well
    3. Severe = > 6 stools per day.  Systemically unwell
    4. Systemic features include tachycardia, fever, anemia, hypoalbuminaemia
  2. Endoscopic grading of ulcerative colitis
    1. 0 = normal
    2. 1 = loss of vascular pattern or granularity
    3. 2 = Granular mucosa with contact bleeding
    4. 3 = Spontaneous bleeding
    5. 4 = Ulceration
  1. Crohn’s disease
    1. Clinical features depend on site of disease
    2. 50% have ileocaecal disease
    3. 25% present with colitis
    4. Systemic features are more common than in ulcerative colitis
  • Extraintestinal manifestations
    Associated with disease activity
  1. Skin
    1. Erythema nodosum
    2. Pyoderma gangrenosum
  2. Joints
  • non-deforming arthropathy
  1. Eyes
    1. Anterior uveitis
    2. Episcleritis
    3. Conjunctivitis
  2. Hepatobiliary conditions
    1. Acute fatty liver
    2. Thromboembolic disease
  3. Unrelated to disease activity
    1. Joints
  • Sacroilitis
  • Ankylosing spondylitis
  1. Hepatobiliary conditions
  • Primary sclerosing cholangitis
  • Cholangiocarcinoma
  • Chronic active hepatitis
  • Gallstones
  1. Amyloid
  2. Nephrolithiasis
  • Treatment
  1. 5-Aminosalicylic acid
    1. Used in mild / moderate ulcerative colitis and Crohn's disease
    2. 5-ASA block production of prostaglandins and leukotrienes
    3. Sulfasalazine was first agent described
    4. Now compounds available to release 5-ASA at site of disease activity
    5. Mesalazine is conjugated to prevent absorption in small intestine
    6. Topical preparation may be used in those with left-sided colonic disease
    7. Maintenance therapy of proven benefit in those with ulcerative colitis
    8. Of unproven benefit in those with Crohn's disease
  2. Corticosteroids
    1. Often used in those in whom 5-ASA therapy is inadequate
    2. Also used in those presenting with acute severe disease
    3. Can be given orally, topically or parenterally
    4. Use should be limited to acute exacerbations of disease
    5. Of no proven value as maintenance therapy in either ulcerative colitis or Crohn's disease
    6. Use must be balanced against side effects
  3. Immunosuppressive and immunomodulatory agents
    1. Often used in those in whom steroids can not be tapered or discontinued
    2. Agents used include:
      1. Azathioprine -effective in both ulcerative colitis and Crohn's disease
      2. Methotrexate - effective in Crohn's disease
      3. Cyclosporin
      4. Inflixitab - anti-TNF-alpha therapy
  • Surgery for inflammatory bowel disease
  1. Indications for surgery - Ulcerative colitis
    1. 20% of patients with ulcerative colitis require surgery at some time
    2. 30% of those with total colitis require colectomy within 5 years
  2. Emergency
    1. Toxic megacolon
    2. Perforation
    3. Haemorrhage
    4. Severe colitis failing to respond to medical treatment
  3. Elective
    1. Chronic symptoms despite medical therapy
    2. Carcinoma or high grade dysplasia
  4. Surgical options
    1. Emergency
      1. Total colectomy `with ileostomy and mucus fistula
    2. Elective
      1. Panproctocolectomy and Brooke ileostomy
      2. Panproctocolectomy and Kock continent ileostomy
      3. Total colectomy and ileorectal anastomosis
        • Maintains continence but proctitis persists
      4. Restorative proctocolectomy with ileal pouch
  • Need adequate anal musculature
  • Need for mucosectomy unclear
  • May need defunctioning ileostomy
  • Pouch designs –Inverse J shape Pouch
  1. Functional results of ileoanal pouch
    1. Mean stool frequency is six per day
    2. Perfect continence
    3. During day (90%)
    4. At night (60%)
    5. Gross incontinence (5%)
  2. Morbidity
    1. 50% develop significant complications
    2. Small bowel obstruction (20%)
    3. Pouchitis (15%)
    4. Genitourinary dysfunction (6%)
    5. Pelvic sepsis (5%)
    6. Fistula  (5%)
    7. Pouch failure  (6%)
    8. Anal stenosis (5%)
    9. Larger capacity pouches reduce stool frequency
  • Indications for surgery - Crohn’s disease
  1. Absolute
    1. Perforation with generalised peritonitis
    2. Massive haemorrhage
    3. Carcinoma
    4. Fulminant or unresponsive acute severe colitis
  2. Elective
    1. Chronic obstructive symptoms
    2. Chronic ill health or debilitating diarrhoea
    3. Intra-abdominal abscess or fistula
    4. Complications of perianal disease
    5. Surgery should be as conservative as possible
    6. No evidence that increased resection margins reduce risk of recurrence
    7. If possible improve preoperative nutritional state
  3. Surgical Options
    1. Limited resections
    2. 30% undergoing ileocaecal resection require further surgery
    3.  Strictureplasty often successful
    4. Bypass procedures rarely required
Extra Edge:
Important Most Common Sites
· Crohn's disease
· Fistula, perforation and carcinoma in Crohn's disease
· Typhoid ulcer
· Tubercular ulcer
· Small intestinal lymphomas
· Gall stone lleus
Terminal Ileum
· Amebic colitis
· Bleeding in angiodysplasia
· Bleeding in colonic diverticula
Cecum and ascending colon
· Ischemic colitis Splenic flexure
· Colonic diverticula
· Stricture after ischemic colitis
· Volvulus
· Ulcerative colitis
· Colorectal cancer
· Hirschsprung’s disease
  1. Colo-Rectal Cancer
    1. Risk Factors
      • Age: 50.
      • Environmental and Dietary Factors
      1. The observation that colorectal carcinoma occurs more commonly in populations that consume diets high in animal fat and low in fiber has lead to the hypothesis that dietary factors contribute to carcinogenesis.
      2. A diet high in saturated or polyunsaturated fats increases risk of colorectal cancer, while a diet high in oleic acid (olive oil, coconut oil, fish oil) does not increase risk.
      3. In contrast, a diet high in vegetable fiber appears to be protective.
      4. A correlation between alcohol intake and incidence of colorectal carcinoma has also been suggested.
      5. Ingestion of calcium, selenium, vitamins A, C, and E, carotenoids, and plant phenols may decrease the risk of developing colorectal cancer.
      6. Obesity and sedentary lifestyle dramatically increase cancer-related mortality in a number of malignancies, including colorectal carcinoma.
        This knowledge is the basis for primary prevention strategies to eliminate colorectal cancer by altering diet and  lifestyle.
        1. Genetic or Family Predisposition: There are two classifications of these genetic disorder:
          Autosomal dominant:
          Familial Polyposis Syndromes – 5th chromosome association
          -  APC gene mutation or deletion
          -  Contribute 1-2% incidence of colorectal cancer.
          - 100% risk of colorectal cancer if FAP.
          - Prophylactic colectomy is the primary treatment.
          - Surveillance for FAP should begin at the age of 10-12 with annual endoscopy examination.
Gardner syndrome - FAP associated with desmoids, Osteomas, Retinal pigment hypertrophy.
Turcut syndrome – FAP associated with brain tumor (Medulloblastoma)
  1. Atleast 100 colorectal adenomatous polyps
  2. Family history of FAP and atleast one of the following: epidermoid cyst; osteomas; desmoid tumor.
    1. Adenomas detectable at endoscopic examination (sigmoidoscopy) between ages of 10 & 20 years of age; increasing in number & size with age
    2. Most important is invariable progression of one or more adenoma to cancer.
    3. Mean age of cancer development is 40 years.
    4. In early stages → no signs/symptoms but can cause bleeding and diarrhoea often accompanied by mucous discharge and abdominal pain.
    5. Screening method — serial flexible sigmoidoscopy. (should be arranged for all children of an affected FAP parent from age of 10 to 15 years and continued at 1 to 2 year interval upto age of 40 years)
    6. Best treatment is prophylactic colectomy or proctocolectomy with ileoanal anasto mosis.
  1. Extra intestinal manifestations
    1. Gastric adenomas (most common is fundal polyp)
    2. Increased incidence of hepatoblastoma
    3. Dysplasia in the bile ducts and gall bladder epithelium.
  2. Extra Gastro intestinal Manifestations Q
    1. Soft tissues → 4 Desmoid tumor
    2. Bone → Exostoses (in long bones) and endostoses (in mandible)
    3. Dental abnormalities
    4. Eye → 75-80% have patches of congenital hypertrophy of retinal pigment epithelium
    5. Skin → Epidermal cysts
    6. Endocrine system → 4 neoplasia of pituitary, pancreatic islets & adrenal cortex, MEN 2b
    7. Nervous system → brain tumor (Turcot syndrome) medulloblastoma.
  • Hereditary Nonpolyposis Colon Cancer (HNPCC) Lynch Syndrome
    - It is DNA Mismatched Repair (MMR) genes mutation.
    - Lynch I Lynch II syndrome is a nonpolyposis autosomal dominant disease.
    - HNPCC occurs five times more frequently than familial polyposis.
    - HNPCC accounts for 5-7% of colon cancer.
    - Isolated early onset of colorectal cancer occurs in the lynch I syndrome.
    - Colorectal cancer and tumor of the endometrium overy stomach small bowel, hepatobiliary tract, pancreas, ureter and renal pelvis charecterise the lynch II syndrome.
  1. Characterized by 3 or more relatives with histologically documented colorectel cancer (one of whom should be first degre relatives)
  2. Mean age of adenocarcinoma is <50 years
  3. Inflammatory Bowel DiseasesQ
    1. Ulcerative colitis → premalignant condition with duration and extent of disease being major risk factors.
    2. Crohn’s disease → 3 times normal risk; long duration & early onset are risk factor for carcinoma
    3. Streptococcus bovis bacteremia
    4. ureterosigmoidostomy
    5. smoking and alcohol use (not proved)
    6. vegetable consumption, NSAIDS, Oestrogen replacement therapy and physical activity associa ted with decreased risk.
    7. Irradiation → rare but well recognized aetiological factor.
Criteria for HNPCC syndrome (Amsterdam criteria)
  1. At least one family member who has developed colorectal cancer by age 50.
  2. Colorectal cancer involving at least two successive generations.
  3. Histologically verified colorectal cancer in three or more relatives, one of whom is a first degree relative of the other two.
  4. There are other medical conditions, which may predispose one to the development of colon cancer; these are ulcerative colitis and Crohn's disease. 
    1. Medical Factors: Intestinal polyps (noncancerous mushroom-shaped growths), chronic inflammatory bowel disease (ulcerative colitis or Crohn's colitis).
Sigmoid cancer: Mimic diverticulitis, presenting c pain fever
  1. Sigmoid cancers can mimic diverticulitis, presenting with pain, fever, and obstructive symptoms.
  2. At least 20% of patients with sigmoid cancer also have diverticular disease, making the correct diagnosis difficult at times.
  3. Sigmoid cancers can also cause colovesical or colovaginal fistulas. Such fistulas are more commonly caused by diverticulitis, but it is imperative that the correct diagnosis be established because treatment of colon cancer is substantially different than treatment of diverticulitis.
Clinical Presentation
Caecum & ascending colon Transverse & descending colon
  1. Stool is relatively liquid
  2. Doesn’t lead to obstruction or noticeable change in bowel habits
  3. Commonly ulcerate, leading to chronic, insidious blood loss without a change in appearance of stool. (fungating also)
  4. Symptoms: fatigue, palpitations angina pectoris & iron deficiency anemia.
  1. stool become more concentrated.
  2. Tumors arises here tend to impede passage of stool, resulting in abdominal cramps, occasional obstructive and even perforation.
Right-sided lesions
  1. Iron deficiency anaemia due occult GI Blood loss
  2. Weight loss
  3. Right iliac fossa mass
Left-sided lesions
  1. Abdominal pain
  2. Alteration in bowel habit, increading constipation.
  3. Rectal bleeding
  4. 40% present as a surgical emergency with either obstruction or perforation
Rectal Cancer: Bleeding- (most common symptom- in 60% of patients may be accompanied by the passage of mucus); Change in bowel habits- (43% of patients, Often in the form of diarrhea or change in the caliber of the stool. Large tumors can cause obstructive symptoms); Tumors located low in the rectum can cause a feeling of incomplete evacuation and tenesmus; Abdominal pain or peritonitis from perforation
  • Symptoms
  1. Abdominal pain,
  2. Altered bowel habits,
  3. Occult bleeding,
  4. Intestinal obstruction.
Right-sided colon cancers tend to be larger and more likely to bleed, whereas left-sided tumors tend to be smaller and more likely to be obstructing.
  • Diagnosis
  1. Carcinoembryonic antigen
    CEA may also be elevated in
    1. Pancreatic and
    2. Hepatobiliary disease
  • Imaging Studies:
  1. Chest x-ray: It may reveal metastatic spread to the lungs.
    Computed tomographic scanning
    1. Investigation of choice is colonoscopy and biopsy.
    2. Abdominal/pelvic CT scans can be useful in diagnosis of colon cancer that has metastasized to lymph nodes and liver.
    3. CT scans also are very helpful in the follow-up of patients with resected, as well as metastatic, disease. Imaging can diagnose recurrent disease and can document response to chemotherapy.
    4. Procedures: Flexible sigmoidoscopy is a screening tool that can detect polyps or cancers as far as 60 cm from the anus.
    5. Double-contrast barium enemas (Apple core like appearance) are an option for screening for colorectal cancer and can aid in establishing the diagnosis of colon cancer.
    6. CT-Scan is the imaging modality of choice.
    7. Whole body PET is the most accurate diagnostic test for recurrent colorectal cancer.
  • Staging
  1. Modified Duke Staging System
  2. TNM Staging
  3. Stage Grouping
Modified Duke Staging System
Modified Duke A The tumor penetrates into the mucosa of the bowel wall but no further.
Modified Duke B B1: tumor penetrates into, but not through the muscularis propria (the muscular
layer) of the bowel wall.
B2: tumor penetrates into and through the muscularis propria of the bowel wall.
Modified Duke C C1: tumor penetrates into, but not through the muscularis propria of the bowel
wall; there is pathologic evidence of colon cancer in the lymph nodes.
C2: tumor penetrates into and through the muscularis propria of the bowel wall;
there is pathologic evidence of colon cancer in the lymph nodes.
Modified Duke D The tumor, which has spread beyond the confines of the lymph nodes (to organs such as the liver, lung or bone).
  • Predictors of Poor Outcome following total surgical resection of colorectal cancer.
  1. Tumour spread to regional lymph nodes
  2. Number of regional lymph nodes involved
  3. Tumour penetration through the bowel wall
  4. Poorly differentiated histology
  5. Perforation
  6. Tumour adherence to adjacent organs
  7. Venous invasion
  8. Preoperative elevation of CEA titer (>5.0 ng/mL)
  9. Aneuploidy
  10. Specific chromosomal deletion (e.g. allelic loss on chromosome 18q)
  • Treatment
    Surgery - Surgical option is the treatment of choice.
    • Right hemicolectomy – For Lesion in right colon
    • Extended right hemicolectomy – For lesion in transverse colon
    • Left hemicolectomy -  For Lesion in left colon
    • Extended left hemicolectomy – For lesion sigmoid colon.
    • Transverse colectomy – For early lesion in transverse colon
    • Sigmoid colectomy – For early lesion in sigmoid colon.
This is the most common and usually the first treatment for patients who have colorectal cancer.
  1. Surgery induced resection of colon with sufficient margins with radical enbloc resection of mesentery & L.
  2. Surgery done both for curation & palliation.
  3. Concomitant use of 5. FU with leucovorin improves the efficacy.
  4. Colorectal operations one “CLEAN CONTAMINATED”
  5. Hartman’s operation → done in old & febrile patients who cannotwith-stand A.P.R.
Chemotherapy  (Recent Advances)
Indication of Chemotherapy      
- Stage III, IV
-  Puke C and D
-  Selected stage II patents

Eloxatin (Oxiliplatin)
  1. Eloxatin is a platinum-based anticancer drug used to treat colorectal cancer that has recurred or advanced colorectal cancer. It is administered intravenously in combination with 5-fluorouracil plus leucovorin (5FU/LV).
  2. Chemotherapy for metastatic disease combination of 5-FU, leucovorin & oxiliplatin with BEVACIZUMAB.
  3. Immunotherapy – BCG is being investigated as adjuvant mixed with autologous tumor cells.
    1. Role of radiotherapy in colonic carcinoma

      1. Pain relief and palliation
      2. Rectal cancer – neoadjuvant is patent with tumors that extend outside rectum or have regional LN, 
Recent Advances: Gene therapy
Vaccine has been developed and tested with promising results, named Trovax

Diagnostic algorithm for rectal cancer (Ref: Schwartz's Principles of Surgery 9th Edition Ch 29)

Extra Edge:
Treatment Options for Carcinoma Rectum
Low Anterior Resection
  • Sphincter saving operation
  • Performed for the cancers of proximal third to two third of the rectum (Located >5 cm above? the anal verge)
  • Descending colon is anastomosed with the distal rectum
Abdominoperineal Resection
(APR or Miles Procedure)
  • Complete excision of rectum and anus, by concomitant dissection through the abdomen and perineum with creation of permanent colostomy",
  • Performed for carcinoma of lower rectum (at or below 5 cm from anal verge)
Hartmann's Procedure
  • When there is too much destruction or sepsis to allow a safe anastomosis?
  • For elderly or severely unstable patients? who would not stand a lengthy anterior resection or APR procedure

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