Principles of oncological surgery

Question 1

List 5 roles of surgery in cancer management

Answer 1

Diagnosis (biospy) 
Resection for cure (definitive excision)
Palliation (remove clinical signs)
Debulking (cytoreductive therapy)
Prophylaxis of neoplasia

Question 2

Define biopsy

Answer 2

retrieval of cells or tissues form tumour to allow a Dx and prognosis (grading and staging) to plan appropriate therapy and allow owner to make decision about therapeutic options

Question 3

Indications - biopsy - 3

Answer 3

• If treatment type (surgery/radiation/chemo) or extent (conservative/aggressive) would be altered by knowing the tumour type
• If owner’s willingness to treat animal would be altered ny knowledge of tumour type, grade, prognosis and clinical stage.
• If lesion is in ‘difficult’ area

Question 4

What information can be gained from biopsy?

Answer 4

Neoplastic or non-neoplastic
Benign/malignant?
Cytological or histologic type
Grade
Margins (if excisional biopsy)
Potential sites for metastases (if LNs or other organs sampled)

Question 5

Guidelines - tumour biopsy

Answer 5

Site should lie within likely surgical field
Minimal risk of tumour dissemination
Fresh instruments for each site
Don’t worsen the prognosis
Longitudinal incisions for distal locations
Avoid tissue that would be difficult to resect or close
Large biopsy more likely to reach diagnosis
Careful tissue handling - avoid forceps and electrocautery
10% formalin fixation, tissues < 1cm thick
Detailed history

Question 6

Define and outlien prophylactic tumour surgery

Answer 6

Remove tissue to reduce incidence of tumour occurence and recurrence rate
Normal or abnormal tissue

Question 7

What does elective gonadectomy reduce the incidence of?

Answer 7

Decreases the incidence of mamary tumours, perianal adenomas, testicular tumours and willr educe the rate of recurrence of vaginal leiomyomas.

Question 8

What might removal of lesions suspected to be pre-cancerous do?

Answer 8

May prevent the development of malignant disease susbsequently - eg. SCC in-situ from the skin of white cats and adenomatous rectal polyps.

Question 9

Contraindications - tumour biopsy - 3

Answer 9

If treatment plan wouldn’t be changed
No change in owner’s willingness to treat
If biopsy is difficult

Question 10

Indication - surgery with curative intent

Answer 10

Localised disease (only)

Question 11

Advantages/disadvantages of complete surgical excision

Answer 11

ADVANTAGES: immediate cure, not carcinogenic, no local toxic effects, not immunosuppressive, better for large masses

DISADVANTAGES: local cure only, change in cosmesis, change in function

Question 12

Principles - surgical excision - 5

Answer 12

• Establish Dx, plan surgery
• Perform surgery early in disease course
• First surgery has the best chance of success
• Adequate margins needed in 3D
• Margin of excision shouldn’t be compromised by concerns regarding closure

Question 13

Why is it important to get tumour removal surgery right first time?

Answer 13

• untreated tumours have normal regional anatomy
• recurrent tumours may have seeded into previously non-involved tissue planes and it can’t be predicted where tumour cells will extend and a wider resection may be required.
• The most active and invasive parts of the tumour are at the periphery - incomplete excision leaves aggressive cells behind
• There is less normal tissue if surgery has been performed previously

Question 14

Common reasons for failure of definitive tumour excision

Answer 14

Failure to plan surgery (usually failure to biopsy)

Failure to stick to the plan, usually concerns over closure

Question 15

What information should be available before surgical procedure is selected?

Answer 15

Histologic type, grade and clinical stage
Expected local and systemic effects of above
Surgery indicated?
Cure possible?
Alternative and adjunctive procedures

Question 16

What additional practical considerations are there for oncologic surgery? 9

Answer 16

Consideration of effect on cosmesis and function
Pre-operative patient prep
Dissection technique
Reduction of tumour cell contamination in surgical field
Avoidance of wound complications
Vascular occlusion techniques
Management of regional LNs
Reconstruction of resulting deficit
Evaluation of the resected tissue

Question 17

What may interfere with local defence mechanisms to removal any remaining tumour cells after surgery?

Answer 17

haematoma, seroma or wound infection

Question 18

Outline vascular and lymphati occlusion techniques

Answer 18

Ligate as early as possibly
Particularly important for tumours where exfoliation or dissemination of cells is likely or for tumours which usually metastasise via the haematogenous (sarcomas) or lymphatic (carcinomas) routes.
Theoretically, ligation of venous and lymphatic drainage should be performed before arterial suppy

Question 19

Which tumour type is more likely to metastasise to regional LNs?

Answer 19

epithelial tumours much more likely than mesenchymal tumours.

Question 20

Causes - regional lymphadenopathy

Answer 20

Metastasis - poor prognosis

Reactive hyperplasia - infection, inflammation, release of factors - may be indicative of a beneficial response

Question 21

Result of lymphadenopathy due to tumour metastasis

Answer 21

generally results in complete effacement by tumour cells and a Dx may be made by FNA

Question 22

Indications - LN removal

Answer 22

• If positive for a tumour and is not fixed to surrounding tissues (generally alone, en bloc resection of tumour, LN and intervening lymphatics may be performed in some cases)
• Normal-appearning LNs which drain the primary tumour maybe sampled to stage the tumour

Question 23

Contraindications - LN removal

Answer 23

• LNs in critical areas which are fixed to the surrounding tissue. Biopsy or leave in situ

Prophylactic removal of normal-appearing LNs without intention of sampling them to stage the tumour has no benefit and may reduce any beneficial host response to the tumour.

Question 24

Name 3 common types of surgical margin

Answer 24

Local excision
Wide local excision
Radical local excision

Question 25

Define local excision

Answer 25

the tumour is removed through its natural capsule, immediate boundaries or with the minimum of adjacent tissue

Question 26

LOCAL EXCISION:
Indications
Contraindications

Answer 26

INDICATIONS: benign tumours with no tendency for local infiltration - lipoma, histiocytoma, sebaceous adenoma

CONTRA-INDICATIONS: invasive benign tumours, all malignant tumours.

Question 27

Define wide local excision

Answer 27

tumour is removed with a substantial margin of surrounding tissue, margins depend on individual tumour.

Anatomical determinants may dictate whether the selected margins will be feasible from a practical point of view, but they should never be the primary determinant in the selection of the appropriate margin.

Question 28

WIDE LOCAL EXCISION:
Indications
Contraindications

Answer 28

INDICATIONS: benign tumours with the capacity for local infiltration (infiltrating lipoma), malignant tumours with limited potential for infiltration (WD SCC)

CONTRA-INDICATIONS: malignant tumours with the potential for local infiltration

Question 29

Define radical local excision

Answer 29

tumour is removed together with margins that extend into adjacent fascial planes which are undisturbed by tumour growth.

Question 30

RADICAL LOCAL EXCISION:
Indications
Contraindications

Answer 30

INDICATIONS: tumours whose rapid radial expansion results in teh development of a circumferential zone of compressed tissue or pseudocapsule

Question 31

What is a pseudocapsule

Answer 31

the capsule around the tumour
contains tumour cells
using this as a guide in the selection of surgical margins is likely to result in complete excision.
Sarcomas (extend along rather than locally through fascial planes)

Question 32

Techniques for radical local excision

Answer 32

Compartmental excision
Muscle group excision
Amputation

Question 33

What is compartmental excision

Answer 33

A type of RADICAL LOCAL EXCISION
Tumour is removed within an intact anatomic compartment such that it is surrounded on all aspects by fascial planes that have not been disturbed by the growth of the tumour.
All BVs and nn which lie within the compartment are removed intact during the procedure.
Generous margin of overlying skin removed where appropriate.

Question 34

Define muscle group excision

Answer 34

the tumour is removed along with the entire muscle it involves

INDICATIONS = small tumours involving muscle bellies in which the fascial planes haven’t been breached or have been breached on an outer aspect where the tissue may also have been removed.

Question 35

Indications - amputation

Answer 35

Large tumours for which a compartmental of muscle group excision is not practical

• Where a radical excision requires resection of a bone or joint
• The management of tumour recurrences where the anatomic compartments have been disturbed by previous surgery and recognition of fascial planes would be difficult
• resections that would severely impair limb function
• malignant tumours with signficant capacity for local infiltration

Question 36

What are resected tumour tissues evaluated for?

Answer 36

Histological type
Histological grade
Regional LN status
Margins
Vascular or lymphatic invasion

Question 37

What is cytoreductive therapy

Answer 37

Cytoreductive (debuling therapy) is the planned incomplete removal of the tumour to improve the efficacy of other treatment modalities (chemo or radiotherapy).

The term ‘debulking’ should be avoided so that cytoreductive surgery and palliative surgery (both of which remove most but not all of the tumour) may be considered separately.

Question 38

When might surgery be regarded as cytoreductive? 4

Answer 38

IF:

• complete excision is precluded by the need to retain essential anatomic structures
• surgery is performed following a previous unsuccessful attempt at excision
• local recurrence is likely
• tumour type has a high rate of local recurrence

Question 39

Define palliative surgery

Answer 39

an attempt to improve patient’s QoL but not necessarily their length of life
Pain relief or improve function