INTRODUCTION: Sir William Arbuthnot was one of the early proponents of the usefulness of total colectomies. Colectomy is commonly performed for the treatment of colon cancer.

DEFINITION: Colectomy implies the surgical resection of any extent of the large intestine (colon). Based on the segment of colon removed colectomies are termed as

1.   Right hemicolectomy.

2.   Extended right hemicolectomy

3.   Transverse colectomy

4.   V resection

5.   Left hemicolectomy

6.   Extended left hemicolectomy

7.   Sigmoidectomy

8.   Proctosigmoidectomy

9.   Total colectomy

10.   Total proctocolectomy

11.   Subtotal colectomy DIFFERENTIAL DIAGNOSIS:

·  Polyps

·  Inflammatory bowel disease-ulcerative colitis, Crohn’s disease

·  Tuberculous stricture of the large bowel with obstruction 21

·  Vascular malformations with lower gastro intestinal bleeding

·  Amoebiasis

PREVENTION: In familiar situations like FAP & HNPCC early colectomy is advised. It is important to understand the carcinogenesis in colorectal cancer & the associated molecular events.

ENVIRONMENTAL FACTORS also pay an important role, particularly dietary factors & estrogen replacement. Association between hyperplastic polyposis & colorectal cancer & adenomas called sporadic MIS tumours Colorectal cancers: are Sporadic in 75% cases & Genetic in 25% (younger age at diagnosis) Positive Familial history is present in 15%-20%. HNPCC (5%)-80% risk FAP (less than 1%)-100% risk of development of CRC – prophylactic total colectomy/proctocolectomy COUNSELLING:

GENETIC COUNSELLING PREDISPOSITION SHOULD BE COUNSELLED & SCREENED

FOR COLON CANCER. Screening colonoscopy and polypectomy – reduces colon cancer mortality.

1.      OPTIMAL DIAGNOSTIC CRITERIA: Situation 1 Clinical Diagnosis Anatomical locations and clinical manifestations of colon cancer Distribution % Ascending

/ Caecum Transverse Descending/Sigmoid Manifestations Bleeding Anaemia Malena Abdominal pain Mass obstruction Abdominal pain Obstruction Mass Changing bowel habit Obstruction Mass Abdominal pain Mass 22 Diarrhoea obstruction Perforation Low back pain

2.      INVESTIGATIONS:

§  Hemogram

§  Colonoscopy – investigation of choice

§  - Biopsy & HPE - Brush cytology if biopsy is not possible

·  X-ray abdomen – if patient presents with features of large bowel obstruction

·   Double contrast barium enema : - When colonoscopy is contra indicated or not available - Findings – constant irregular filling defect - Detects associated lesions - Small ulcerative lesions can be diagnosed

·  USG abdomen

·  Endoluminal ultrasound – if available

·  CECT – if available is used in large palpable abdominal masses = To determine local invasion

·    Urograms – when evidence of hydronephrosis on USG/ CT in left sided tumours

3.      TREATMENT:

1.    Pre op evaluation of staging, respectability, patient’s operative risks are mandatory.

2.   Accurate localization of tumour – of particular importance.

a.    Sometimes known cancer may not be apparent on serosal aspect.

b.    Localization by tattooing during colonoscopy, Barium enema.

c.    Pre op CT, USG assessment of iver metastasis should be done

PRE-OP PREPARATION: Mechanical bowel preparation Prophylactic antibiotics 23 Blood grouping and cross matching Thromboembolism prophylaxis

OPERATIVE TECHNIQUES: Resection should follow Standard oncological principles:

·  Proximal ligation of primary arterial supply at its margins

·    Adequate proximal & distal margins (5 cm) determined by area supplied by the primary feeder artery

·  Appropriate lymphadenectomy – harvesting of minimum 12 nodes

·  Extent of resection is an important prognostic factor (SAGES guidelines 2000)

·      Any tumour not removed intraoperatively strongly influences prognosis & therapy

Ro – absence of residual tumour, margins free histologically

R1 – no gross residual tumour but margins histologically positive R2 – residual gross disease remains unresected

RADIAL MARGIN:

T4 lesions are a complex group & should be considered separate from other T groups Radial tumour free margins should be resected. Radial margin should be histologically free of disease for resection to be curative. Specimen labelling, marking are important for a good pathological report R1 & R2 resection – incomplete resection for cure affects curability though TNM stage remains same

LATERAL CIRCUMFERENTIAL MARGIN: In addition to radial, proximal & distal margins, circumferential margins should also be pathologically assessed. Positive margins are associated with increased rate of local and distal failure. Disease free survival and mortality significantly related to margin involvement after

TME ADJUVANT Ro stage: Adjuvant therapies require complete resection A case is not Ro if it is 24

§  Non enbloc resection

§  Radial margins positive for disease

§  Bowel margin positive for disease

§  Residual lymph node disease present or

§  Nx (incomplete staging)

LYMPHADENECTOMY: Should be radical (up to the level of origin of primary feeding artery) Apical nodes positive for disease may have prognostic significance in addition to number of positive lymph nodes

ENBLOC RESECTION of adherent tumours: En bloc removal of adjacent organs locally invaded by cancer colon can achieve survival rates similar to patients with tumour that do not invade an adjacent organ, provided negative resection margins are achieved.

PERFORATION OF TUMOUR SHOULD BE AVOIDED (SAGES GUIDELINE)

Inadvertent full thickness perforation of rectum would probably classify tumour as T4 and resection as R1 Perforation at the site of cancer, as opposed to an area remote from the tumour has a greater impact on survival & local recurrence. Inadvertent local perforation predisposes to local recurrence and warrants post-operative radiotherapy.

INTRAOPERATIVE SPILLAGE: HAS AN INDEPENDENTT EFFECT ON

PROGNOSIS Adjuvant radiotherapy may be considered to decrease rates of local recurrence NO TOUCH TECHNIQUE: Value inconclusive 25

SURGICAL PROCEDURES: Anatomical Resection of Colon Cancer Tumour location Vascular Ligation Colon resection Anastamosis Caecum, ascending colon ileo-colic, right colic Right hemicolectomy ileotransverse colostomy Hepatic flexure, Proximal transverse colon ileocolic right, middle colic Extended right hemicolectomy with omentectomy iIeodescending colostomy

Distal transverse colon splenic flexure ileocolic right, middle or left branch of middle colic, left colic Extended right hemicolectomy with omentectomy or Left hemicolectomy ileosigmoid colostomy or Transverse sigmoid colostomy Descending colon Inferior mesenteric or left colic Left hemicolectomy Transverse colorectal anastamosis Sigmoid colon Inferior mesenteric or sigmoid Left colectomy or Sigmoid resection Transverse colorectal anastamosis or descending colorectal anastamosis Colectomy may be performed by the i) Conventional open technique

REFERRAL CRITERIA: Patients suspected of colon cancer & biopsy proven should be referred to a higher centre for further evaluation and treatment when

1)    Adequate surgical facilities are not available / surgeon does not have sufficient experience in colon cancer surgery.

2)    Competent pathologist to report on malignant lesions as per standard oncological guidelines is not available.

3)  For adjuvant / neo-adjuvant radio and chemo therapy

TREATMENT: Patient requiring colectomy for biopsy proven cancer are best referred to a super specialty centre In view of the need for multi-modality treatment.

SITUATION 2: All investigations as in situation 1

·    Spiral CT in elderly patients more than 80 years

·    CT colonoscopy also called virtual colonoscopy – 6 mm polyps may be picked up effectively

·      CEA – fetal glycoprotein - Increased pre op CEA in node positive Ca –indication for chemotherapy

·    MRI :

· PET : detection of metastasis

·    SPECT – if single photon emission is studied, such as technetium or thallium

·    FDG-PET – useful in evaluation of recurrent colorectal cancer -Differentiates post op changes from recurrent / residual disease -Useful diagnostic tool but prohibitive cost

·    CT-PET – fusion tests provide the most powerful integrated images

·      NUCLEAR MEDICINE IMAGING: -Using 131 I , 111 In, 99m Tc bound to monoclonal antibodies, leucocytes & erythrocytes.

TREATMENT: As outlined in situation 1. Laparoscopic resection is gaining popularity. However, it is not freely available & performed as per protocols.

SPECIAL CONSIDERATIONS

1.        Synchronous malignancies or polyps Patients with synchronous malignancies should be considered for subtotal colectomy depending on the distance between lesions Colonic cancer with multiple adenomatous polyps – subtotal colectomy 27 (Due to increased risk of metachronous lesion and to facilitate surveillance of the remaining colon) Factors that influence the decision to perform prophylactic subtotal colectomy -number -location -size of accompanying polyps -age -compliance of patient

2.   Cancer is a polyp Complete endoscopic removal of polyp with cancer in situ – no further treatment Histoplathology shows invasive carcinoma: Ensure that endoscopic polypectomy was complete Specimen was submitted with proper orientation to the pathologist for histopathology Carcinoma at margin of resection requires formal resection Carcinoma with free margins – a. thorough pathological review, b. identification of adverse histological features i. poor differentiation, ii lymphatic or venous invasion iii invasion into the stock of the polyp – formal resection It is difficult to locate the previous polypectomy site during surgery Even if polyp is not removed it may be soft and difficult to palpate through the colon wall 28 Endoscopic distance (from anal verge or dentate line) misleading Polypectomy site should be videotaped for later review and marked with vital dye that can be seen serosally at the time of surgery

3.   Obstructing Cancers- 2% of colorectal cancers Partial obstruction – Gentle bowel preparation over several days-Elective surgery Total obstruction - Rt colon cancers – Rt Hemi colectomy – immediate ileocolostomy - Lt colon cancers

1)   Endoscopic decompression by laser passed beyond the obstructed Segment – This allows mechanical preparation and elective resection. - This is possible only when the narrowed lumen can be traversed by the endoscope. - It is not possible when obstruction is complete

2)   Primary resection and immediate anastamosis with ontable colonic washout with or without proximal colostomy.

3)  Primary resection with colostomy. Anastamosis at second stage.

4)  Subtotal colectomy with primary anastamosis

5)  Decompressive colostomy followed by formal colonic resection

4.   Adjacent organ involvement- 10% Locally advanced tumours are potentially curable with multi organ resection.-Do not necessarily Portend a dismal prognosis. -A non metastasizing variant of colon cancer grows to a large size without spreading to regional nodes -Separation of adhesions adjacent to a malignancy can lead to dissemination of tumour cells. 29 -Enbloc resection of these tumours, depending on location can lead to five year survivals of 70% Hepatic metastases – 10% at the time of exploration. -Solitary metastasis amenable to –wedge resection with clear margins can be removed concomitantly. -Formal hepatic lobectomy done as a second stage procedure.

5.   Ovarian metastasis – 7% at the time of colon resection Oophorectomy: at the time of colorectal surgery Indications i) Large ovarian metastasis (Krukenbergt’s tumour) which are symptomatic (prevents second surgery for the metastasis, benefit of preventing primary ovarian cancer) ii) Direct ovarian involvement iii) Post menopausal women – prophylactic oophorectomy 6. Inadvertent Perforation -Predisposes to local recurrence -Warrants post op radiotherapy Follow up Aim: Early detection of recurrence or metachronous lesion History Physical examination Faecal occult blood CBC } every 3 months- first 3 years LFT every 6 months additional 2 years 30 Tumour markers (CEA)

- monthly – 3 years, 3 monthly-next 2 years Colonoscopy – first colonoscopy within 6-12 months of surgery, yearly-next 2 years, 2-3 yearly thereafter. CXR CT abdomen and pelvis – if primary loco regionally advanced -LFT ↑ -CEA ↑ 80- 90% of recurrence of colon cancers occurs in the first two years. SOP All patients should be admitted when a colectomy is planned

WHO DOES WHAT?

Doctor: c) Surgeon: diagnosis & work up Pre operative planning Operative procedure Post operative follow up

d)  Radiotherapist : radiotherapy – neoadjuvant & adjuvant

e)  Medical oncologist : Chemotherapy

f)  Anesthetist: PAC, anesthesia, post op ICU management

NURSE: · Siting of colostomy when required by some nurse · Care of stoma · Dressing of the wound · Pre & post operative care 31 TECHNICIAN: · Pre op equipment and drugs to be checked and kept ready · Assist anesthetist in the OT · Assist the surgeon, positioning of the patient