Cancer Treatment: Surgery & Radiotherapy

Question 1

what is an incisional biopsy

Answer 1

Removal of a portion of a mass for analysis prior to more definitive surgery

Question 2

what is an excisional biopsy

Answer 2

Removal of an entire mass with some margin of grossly normal tissue for analysis and also for potential cure

Question 3

what is cytoreductive surgery

Answer 3

Surgery designed to remove gross disease to prepare patient for radiotherapy

Question 4

what are the 6 principles of oncology surgery

Answer 4

1. Resect tumour with appropriate margin
2. Plan biopsy so that tract cab be resected with tumour
3. Consider scars from previous surgery, biopsies + drains as contaminated and include them with the primary resection
4. Ligate the blood supply early to prevent dissemination
5. Limit contamination of surgical field: change instruments, gloves between resection + reconstruction
6. Limit the use of drains

Question 5

why should you consider FNA for all skin masses

Answer 5

Low morbidity

Lipoma + mast cell tumour

Identify most tumours to cell type

Helps plan surgery

Question 6

what if FNA is not sufficient (2)

Answer 6

1. needle core biopsy
2. surgical biopsy - incisional, excisional

Question 7

how is a needle core biopsy done

Answer 7

Tissue collecting channel and outer cutting sheath

Spring loaded needles

Larger samples than FNA

Preserve architecture

Question 8

what can needle core biopsies provide

Answer 8

Histopathological diagnosis

+/- grade: difficult to include normal tissue

Question 9

what can an incisional biopsy provide

Answer 9

Preserves architecture

Deep biopsy to be representative

Staging: include normal margin

Question 10

how is an incisional biopsy done

Answer 10

Wedge shaped incision

Deep is better than wide

Close with horizontal mattress sutures to compress tissues to prevent bleeding

Question 11

how do you plan a biopsy

Answer 11

Ensure doesn’t impede subsequent surgery

Tract contaminated

Excise with margins

Take most direct route through skin

Question 12

what is the radial margin

Answer 12

Margin of skin and associated fat

Question 13

what is the size of the radial margin

Answer 13

1mm-3cm (occasionally 5cm)

Question 14

what is the size of the radial margin dependent on

Answer 14

1. tumour type
2. predicted invasion

Question 15

what is the anatomy of a skin mass

Answer 15

Question 16

what is the deep margin

Answer 16

Biological barriers to tumour spread

Radial margin guidelines impractical

Question 17

what are biological barriers to tumour

Answer 17

Collagen rich tissues:

Muscle belly

Fascia

Periosteum

Bone

(not cutaneous trunci muscle)

Question 18

what should the margin of resection look like

Answer 18

avoid cone shaped

should go straight down

Question 19

what are the options for margins of skin tumours (4)

Answer 19

1. marginal resection
2. local resection
3. wide local resection
4. radical resection

Question 20

what is a marginal resection

Answer 20

Dissect just outside the pseudocapsule of tumour

Question 21

how large are marginal resections

Answer 21

1-2mm margin

may leave microscopic deposits

Question 22

what are the indications of marginal resections (2)

Answer 22

1. lipoma (curative as very benign)
2. cytoreductive beofre radiotherapy

Question 23

what is a local resection for

Answer 23

Bengin, non-invasive masses

mammary tumour (dog), histiocytoma

Question 24

how large are local resections

Answer 24

1cm radial margin

Down to but not through next unaffected fascial plane

Question 25

what is a wide local resection for

Answer 25

for more invasive tumours

Question 26

how large are wide local resection tumours

Answer 26

2-3cm radial margin

Excise deep fascial plane

Question 27

what tumours are wide local resections for

Answer 27

Sarcoma

Mast cell tumour

Question 28

what is radical resection for

Answer 28

very locally aggressive tumours

resection with very wide margins

Question 29

what might radical resection require

Answer 29

Amputation (femoral osteosarcoma)

Question 30

how large are radical resections

Answer 30

3-5cm radial margins

1-2 deep fascial planes

Question 31

what tumour types are radical resections for

Answer 31

SCC

melanoma

feline injection site sarcomas

Question 32

how large would radical resection of a feline injection site sarcoma be

Answer 32

Most invasive and aggressive tumour

Most radical veterinary surgery

5cm radial margins

2 deep fascial plane

Adjunctive radiotherapy/chemotherapy

Question 33

how are body cavity tumours removed

Answer 33

Tumour within organ

Capsule may be effective barrier

Remove whole lobe or organ

Question 34

when would complete surgical excision of a body cavity tumour be used

Answer 34

Aim usually to attempt cure

Complete surgical excision

Assumes tumour has not spread

Mainly aim in general practice with non-invasive tumour types

Question 35

when would surgery be used as part of a multimodal treatment

Answer 35

Margins less important

Radiotherapy to preven local recurrence

Chemotherapy to limit metastatic disease deposits

Common in referral practice for invasive or malignant tumour types

Question 36

what tumours are surgery + radiotherapy key for

Answer 36

Key treatment for invasive tumours:

Mast cell tumour

Soft tissue sarcoma

Question 37

how do surgery + radiotherapy treat invasive tumours

Answer 37

Surgery removes bulk of disease

Radiotherapy kills remaining microscopic tumour deposits

Cytoreductive surgery

Question 38

why use surgery and radiotherapy together

Answer 38

Radiotherapy is effective against rapidly dividing cells

Gross tumour deposits have mainly quiescent cells

Cytoreductive surgery removes all gross disease but anticipates that microscopic tumour deposits remain

Cytoreductive surgery is usually marginal resection or local resection

Question 39

what are the options to submit to see if margins are sufficient

Answer 39

1:10 mass:fixative by volume

10% neutral buffered formalin

Submit all excised tissues

Mark margins with suture or ink