Oncologic surgery principles

Question 1

How common is cancer in dogs and cats?

Answer 1

1/3 dogs will get in lifetime and 1/4 cats

Question 2

What are the 3 main areas for cancer treatment in small animals?

Answer 2

Medical, radiation and surgical management
- multimodal approach often indicated- can reduce the side affects of using just one approach

Question 3

When is surgery and radiation preferred over chemo?

Answer 3

If the disease is local. Use chemo for systemic disease

Question 4

What is the role of surgery in cancer treatment?

Answer 4

Can diagnose and treat solid tumors, can use for palliative treatment, or can use for prevention of cancer

Question 5

What are the common signalments for cancer patients?

Answer 5

Often middle aged to older
-malignant tumors in young dogs tend to be more aggressive
-remember that age is not a disease! Must assess overall health status of each dog as they are
-breed and sex are not prognostic

Question 6

What is a characteristic of most malignant tumors which make them hard to treat?

Answer 6

They have microscopic extensions into the surrounding tissue

Question 7

Why is it important to focus on regional lymph nodes when evaluating a mass in a dog or cat?

Answer 7

Lymph node involvement may indicate metastasis- need FNA of lymph node for definitive answer

Question 8

Can you have metastatic disease with normal lymph nodes?

Answer 8

YES- if worried about metastatic potential, get a sample from the regional lymph nodes

Question 9

T/F: cancer can predispose patients to coagulopathies

Answer 9

TRUE

Question 10

What are the methods for tumor diagnosis?

Answer 10

FNA, needle core biopsy, incisional biopsy, excisional biopsy

Question 11

When should you pursue biopsy?

Answer 11

If the information received from it may change the choice of treatment, extent of treatment, as well as the owners willingness to treat
- biopsies are needed for tumor grading

Question 12

What tumor type is FNA diagnostic for?

Answer 12

MCT

Question 13

When are some conditions that FNAs are contraindicated?

Answer 13

If suspecting a TCC (can seed tumor into abdomen) or adrenal mass (often very sensitive)

Question 14

T/F: you should assume a tumor is malignant until proven otherwise

Answer 14

TRUE- don’t want to make it worse if theres any chance

Question 15

What biopsy tool is used to get a sample of bone?

Answer 15

Jamshidi

Question 16

What are the disadvantages of needle core biopsies?

Answer 16

Sample is small, so may be non-diagnostic or non representative of the lesion
*take multiple samples for higher diagnostic accuracy

Question 17

T/F: you can take biopsies of oral tumors without sedation or local anesthetic

Answer 17

TRUE

Question 18

Define excisional biopsy

Answer 18

Resection of entire gross mass without definitive margins
-not recommended as if you don’t get good margins it will be hard to resect in entirety
-do not take any fascial planes as revision might be needed
-only consider in areas with adequate tissue coverage

Question 19

What are the margins required for injection site sarcomas in cats?

Answer 19

5 cm minimum on each side, 2 fascial planes deep to mass

Question 20

Why is local tumor imaging important?

Answer 20

assessment of tumor location, invasion into adjacent structures, can aid in surgical planning
-can look for distal metastasis

Question 21

How does PET imaging work?

Answer 21

Glucose analogue stays in tissues that utilize a lot of glucose, like tumors
-also accumulates a lot in the brain

Question 22

What does tumor staging depend on?

Answer 22

Local tumor characteristics, regional lymph node metastasis, or distant metastasis

Question 23

What is the biggest mistake made with tumor planning?

Answer 23

Using too low of surgical dose
- your first attempt is your best chance at getting out the full tumor

Question 24

What is recommended for most solid tumors?

Answer 24

Radical or wide resection

Question 25

What is the difference between radical and wide resection?

Answer 25

Radical is removing the organ or part of the body where the tumor is located
-wide is where lateral and deep margins are made very wide to remove both the gross and microscopic tumor cells (amount you resect depends on type of lesion)

Question 26

What margins are recommended for benign masses, grade 1 or 2 MCT, intestinal tumor

Answer 26

benign- 1 cm
MCT- 1 cm lateral per size of mass
intestinal: 4-8 cm

Question 27

What is marginal exision?

Answer 27

Incomplete excision of a tumor with residual microscopic disease
- equivalent to an excisional biopsy
-avoid unplanned resections! know you might be leaving behind cancer cells and that other modalities of treatment may be indicated

Question 28

Why is debulking not recommended?

Answer 28

Presence of macroscopic tumor usually makes adjunctive treatments less effective

Question 29

What are some general principles you should keep in mind when performing surgery on tumors?

Answer 29

Avoid grasping tumor directly with instruments, avoid penetrating tumor capsule, avoid drains, avoid flaps without confirmation of complete margins, always change gloves and instruments in between biopsies or multiple mass resections
-always resect benign tissue before malignant

Question 30

What is reccomended for pathologist examination of masses?

Answer 30

A combo of radial sectioning and tangential sectioning

Question 31

What are the benefits of OHE prior to 3rd heat cycle?

Answer 31

Reduces or eliminates risk of mammary ovarian and uterine tumors