Resection of Tumours

Question 1

What is tumour biology?

Answer 1

What a tumour is and how it behaves

Question 2

What is tumour biology used to dictate?

Answer 2

○ When to operate or not to operate
○ What operation to perform
○ Other therapy
○ What should the surgical margins be?

Question 3

What types of oncological surgery are there?

Answer 3

Prophylactic surgery
Diagnosis and staging
Definitive excision
○ Most commonly used
Palliative surgery
○ Alleviate clinical signs
○ Help for as much time as possible
Cytoreduction
○ Can’t remove it all
○ Could respond well to other therapy
○ Remove as much as possible
Management of oncological emergencies
○ E.g. Bleeding splenic tumour
Surgery for supportive therapy
○ E.g. Placing a feeding tube
Treatment of metastatic disease
○ Rarely occurs in veterinary medicine

Question 4

What is prophylactic surgery?

Answer 4

Preventative surgery
Reduces risk of developing tumour
Example - ovariohysterectomy
○ Significant impact on whether bitch will develop mammary neoplasia later in life

Question 5

What is an oncological emergency?

Answer 5

Any acute possible morbid or life-threatening events in patients with cancer

Question 6

What should you do in an oncological emergency?

Answer 6

Deal with the immediate problem rather than trying to remove tumour
Presented as emergency cases
E.g. bleeding into abdomen due to splenic tumour

Question 7

What is the difference between diagnosis, grading and staging

Answer 7

Diagnosis - tells you type of tumour
Grading - tells you malignant tendencies
Staging - tells you the extent to which a tumour has spread

Question 8

What does a surgeon need to know about the tumour to determine surgical margins?

Answer 8

Type of tumour
Grade

Question 9

How do you determine tumour type?

Answer 9

Cytology
FNA
Impression smears

Question 10

How do you grade a tumour?

Answer 10

Histology
Core biopsy
Punch biopsy
Incisional biopsy
Excisional biopsy

Question 11

How do you stage a tumour?

Answer 11

Radiography
Ultrasound
CT (usually best option)
Occassionally MRI

Question 12

Tumour Terminology - T

Answer 12

Tumour

Question 13

Tumour Terminology - P

Answer 13

Pseudocapsule
○ Compressed cancer cells and fascial layers
○ Appearance of discrete capsule
○ Not an actual barrier
Not connective tissue!

Question 14

Tumour Terminology - R

Answer 14

Reactive
Often has inflammation

Question 15

Tumour Terminology - Sk

Answer 15

Skip metastases
Outside of reactive zone

Question 16

Tumour Terminology - St

Answer 16

Satellite metasteses
Within reactive zone

Question 17

What is the surgical dose?

Answer 17

How much surgery to do

Question 18

What types of definitive surgery are there?

Answer 18

Debulking/intralesional/cytoreduction
Cytoreductive surgery
Going to leave some cancer behind
Marginal excision
Wide excision
Radical excision

Question 19

What is Debulking/intralesional/cytoreduction?

Answer 19

Cutting through a lesion
Leaves macroscopic volumes of tumour behind
Tumour will recur unless given adjuvant therapy (chemo/radiation)

Question 20

What is marginal/local excision?

Answer 20

• Excision immediately outside of pseudocapsule (Within reactive zone)
  
  • Leaves behind microscopic volumes of tumour
  • Minimal amount of surrounding tissue removed
  • Local recurrence likely without adjuvant therapy (chemo/radiation)
  • Why?
    ○ Difficult to close wound
    ○ Difficult to get margins beyond Pseudocapsule

Question 21

What is wide excision?

Answer 21

Removal of all tumour with complete margins of normal tissue in all directions
Local recurrence is unlikely
Outside of reactive zone
Lateral margins can be straight forward
Deep margins can be difficult
Depends on anatomy

Question 22

What tissue makes an effective barrier against the spread of cancer?

Answer 22

Collagen-rich relatively avascular tissues
○ Fascia
○ Ligaments
○ Tendons
○ Cartilage
Sub-cut fat is not particularly effective as a margin
○ Relatively little resistance to invading tumour cells