[Colorectal cancer]

Management

1. History
   • Characteristics of PR bleeding
   • Change bowel habit
   • Weight loss
   • Family history: HNPCC, p53, APC
2. Examination
   • DRE: 90% palpable
   • Inspect glove for blood or mucous
   • Abdomen for masses
3. Investigations
   • Proctoscopy: visualisation, confirmation and biopsy of any lesion
   • Barium enema - identify suspicious lesions
4. Staging
   • Local spread: Endoluminal USS, CT, MRI
   • Metastatic spread: CXR, USS, CT Chest / Abdomen
   • Dukes staging
5. Treatment

Surgical Treatment

1. Ascending colon - Right hemicolectomy
2. Descending colon - Left hemicolectomy
3. Sigmoid colon - Sigmoid colectomy
4. Mid-rectum - Anterior resection + Total mesenteric excision (TME)
5. Low Rectum - Abdomino-peroneal resection

Principles

• Check bowel viability - don't anastamose doubtful bowel
• Absolutely no tension
• End procedure as far as necessary should unexpected pathology be discovered
• Anastasmoses: end-to-side if bowel diameters different; end-to-end if bowel diameters equal; side-to-side if bowel viability in question
• Stoma siting (compromise between lying, sitting and standing positions)

1. Enter peritoneum
2. Perform through laparotomy - assess liver mets, intraabdominal spread, lymphadenopathy, local spread and fixity
3. Mobilise omentum
4. Mobilise small bowel
5. Mobilise large bowel
6. Excise bowel - 2cm adequate / 5cm preferred
7. Ensure tension free anastamosis by adequate mobilisation
8. Consider protecting anastasmosis by proximal defunctioning loop ileostomy

Right Hemicolectomy + Primary anastamosis

1. Enter peritoneum
   • Midline incision / transverse incision (less painful, slimmer patients)
2. Mobilise caecum and terminal ileum
   • dividing lateral peritoneum clockwise and upwards
   • Dissect off right colon
   • Identify and protect the gonadal vessels, right ureter and duodenum
3. Divide bowel
   • Transilluminate the mesentry; ligate vessels close to origin (as close as possible really)
   • Place non-crushing clamps on transverse colon and ileum and divide bowel between crushing clamps
4. Form end to side anastamosis (along taeniae)
   • Close distal end of colon (by hand) or stapling device
   • Approximate ileum with colon and commence posterior wall by inserting seromuscular (Lembert suture)
   • Open colon along taeniae and insert full thickness absorbable suture
   • Continue to midline anteriorly and tie off sutures
5. Close mesenteric defects (prevents herniaetion)
6. Close wound (mass closure etc)

Left Hemicolectomy + Primary anastamosis

1. Enter peritoneum
2. Mobilise colon
   • Divide along white line of "Toldt"
   • Push sigmoid mesentry medially
   • Identify and protect gonadal vessels and left ureter as it crosses pelvic brim
3. Divide bowel
   • Transilluminate mesentery and identify and ligate vessels close to origin
   • Distally ligate vessels at bowel wall
   • Place non-crushing clamps across rectum and proximal bowel
   • Protect wound edges from contamination using abdominal swabs
   • Excise colon
4. Form anastamosis
   • Single-layer technique
   • Stapled gun
5. Close mesenteric defect
6. Washout + close

Hartmann's operation / End colostomy

Indications

• Obstructing lesion in sigmoid colon
• Perforated lesion in sigmoid colon
• Volvulus of sigmoid colon

Pre-op: marking by stoma nurse

1. Enter peritoneum
   • Midline incision
2. Mobilise bowel
   • Divide along white line (avascular plane)
   • Sweep sigmoid off mesentry
   • Identify and protect gonadal vessels and left ureter
3. Divide bowel
   • Transilluminate mesentry, identify and ligate vessels
   • Place non-crushing clamps across distal and proximal bowel
   • Excise diseased segment
4. Close distal colon with two layers of continous sutures
   • Hitch bowel to presacral fascia making it easier for reversa
5. Formation of stoma
   • Bring out proximal colon
   • Circular skin incision 2cm in diameter and deepen to rectus sheath (palpate inferior epigastric vessels to avoid damage at this stage)
   • Make cruciate incision into sheat, bluntly dissect through muscle into peritoneal cavity
   • Place clamp through stoma site and capture proximal colon: manipulate bowel through abdominal wall
   • Approximate skin and bowel edge with interrupted sutures at regular intervals (x6-8 deep: external oblique aponeurosis + superficial: skin)
   • Good practice to pass colon through peritoneum at point lateral to intended stoma site as this creates a tunnel which should reduce the incidence of stomal herniation
6. Washout peritoneal cavity with tetracycline throughout procedure (very high risk of wound infection)

Reversal of Hartmann's

• Only attempt once patient has fully recovered + stoma has matured (3-6 months)
• ~60% are reversed due to persisting morbidity in the patient 

Anterior Resection + defunctioning ileostomy

Indications

• Carcinoma of mid-rectum

1. GA + Lloyd-Davies position + Catheter
2. Enter peritoneum
3. Mobilise bowel
4. Colorectal anastamosis
5. Defunctioning ileostomy

Abdomino-Perineal resection

Indications

• Carcinoma of lower 1/3 of rectum
• Anal carcinoma

Pre-op: irreversible colostomy

1. GA + Lloyd-Davis position + catheter
2. Abdominal component
   • Sigmoid mobilised
   • Protect other structures (ureter, gonadal vessels)
   • Rectum mobilised - identify and protect pre-sacral plexus
   • Divide fascia of Denonvilliers anteriorly (protect seminal vesicles)
3. Perineal component
   • Elliptical incision from coccyx passing lateral to anal verge and finishing at perineal body
   • Deepen to mesorectum to meet abdominal access
   • Divide posterior edge of levator ani
4. Rectum freed and delivered through perineal wound
5. Form stoma from remaining colon
6. Close abdomen
7. Close perineum

Complications

• Reactionary haemorrhage
• Infection - wound, pelvic abscess
• Renal tract injury
• Sexual dysfunction and impotence
• Complications of colostomy - retraction, prolapse, herniation, stenosis, ulceration, ischaemia/necrosis