Principles Of Oncologic Surgery Flashcards
T/F: Malignant tumors in young dogs tend to be more biologically aggressive
T
T/F: Breed and sex are prognostic
F
What should you assess in your general physical exam of a cancer patient?
If there is a primary tumor then you should assess location and mobility (dermis v SQ). Palpate the regional lymph nodes and assess any other tumors
What are 4 methods you can used to dx a tumor?
- Fine needle aspiration
- Needle core biopsy
- Incisional biopsy
- Excisional biopsy
Briefly explain FNAs
FNA’s can categorize samples into epithelial, Mesenchymal, or round cells. They can be diagnostic for some types of tumors such as MCT’s. They’re a good first step because they’re economical, don’t require sedation and rule out non-neoplastic diseases. However, 13-35% of samples are non-diagnostic.
Which types of tumor would you not want to FNA?
TCC or adrenal mass
Does an FNA provide tumor grade?
NO
Biopsy provides ___. What are the 3 types?
Tumor grade
- needle core biopsy
- incisional
- excisional
Briefly explain needle core biopsy
Needle core biopsy often only requires sedation and local anesthesia but it only takes small samples that may not be diagnostic/representative
Briefly explain incisional biopsy
These are typically wedge or punch biopsies that are good for soft, friable or inflamed tissues. They can be performed with sedation (oral), local anesthesia or general anesthesia. The biopsy scar needs to be able to be respected with the tumor
T/F: you should do an incisional biopsy of an oral mass through the overlying lip
F, it would necessitate a more aggressive surgical resection, or RT after surgery, or rend the tumor resection unreasonable
Briefly explain excisional biopsy
Excisional biopsies involves resecting the entire gross mass without definitive margins, this is common but controversial. It is usually diagnostic but not therapeutic
What would be preferable over excisional biopsy?
To get the best results, you should do an FNA or needle core biopsy so you know what you’re working with. Then you can plan a definitive surgical procedure that gives the pet a better MST.
If you do an excisional biopsy then __ take the fascial plane and only consider limbs with sufficient soft tissue coverage, NOT __
DO NOT, distal limbs
What formalin ratio should should you use for biopsy?
10% buffered solution, 1 part tissue to 10 parts formalin
How would you clinically stage a tumor you believe may be malignant?
- Describe the extent of local tumor
- Assess for the presence of local or distal at tumor metastases (rads, UA, CT, MRI, Nuclear Scintigraphy, CT)
- Lymph node staging (enlargement, fixation, symmetry)
What percent of dogs with oral melanoma had normal sized LN but had Mets
40%
What type of margin is recommended for most solid tumors?
Radical or wide
Radical resection
Removal of a body part
Wide resection
Lateral and deep surgical margins to remove the complete tumor burden -> the precise amount of tissue depends on the tumor type and histopathological grade
In wide resection you should take a minimum of __ fascial plane or __ for feline injection site sarcomas
1, 2
Marginal resection
Incomplete excision of a tumor with residual microscopic disease that may need to be followed with alternative treatments such as radiation therapy
This is very likely for limb tumors such as MCT’s or STs
If you have incomplete margins, what are the 4 treatment options?
- No treatment
- Staging resection of the surgical wound
- Wide resection of the surgical wound
- Adjuvant tx
Debulking/intralesional surgery
Just don’t do this, you’re just leaving behind disease
General cancer surgery principles
- Avoid directly grasping the tumor with instruments as this leads to tissue fragmentation and exfoliation of tumor cells
- Avoid penetrating tumor capsule
- Avoid drains
- Avoid flaps without confirmation of complete margins
- Avoid contamination/tumor seeding
What are some general cancer surgery principles?
- Primary wound closure is preferred
- Manage as open wound until confirm clean margins, then reconstruct
- Healing by second intention
- Always submit resected tumors for histology, NOT OPTIONAL
- Submit the entire resected mass
What information should Histopathology provide you?
It should give you the tumor type, grade and margins. This provides important information for risk of local recurrence and Mets, necessity of further treatment and prognosis
