Oncologic Surgery Flashcards
________ is the major cause of death in cats and dogs.
cancer
T/F: optimal treatment for cancer is either surgery, radiation, OR chemotherapy.
false – optimal treatment often requires MULTIPLE modalities not just one or another. Using multiple modalities can maximize the benefits and potential cure, while minimizing the adverse side effects
What role does surgery play in cancer?
- diagnose and treat solid tumors
- palliative treatment
- cancer prevention
Success of oncologic surgery can be broken up into what 2 crucial components?
- patient assessment (assessing general health status, lifestyle, activity levels, and the type + stage of the cancer)
- surgical knowledge
T/F: malignant tumors in older dogs tend to be very aggressive
false – in YOUNG dogs they tend to be biologically aggressive
An 8 yo labrador retriever patient of yours is diagnosed with a cancer that requires amputation of his right rear limb. Upon doing your patient assessment, the owners tell you that he is a big couch potato and sleeps all the time. Is this patient an ideal candidate for surgical cancer treatment?
yes – this dogs lifestyle of being a couch potato means that he will likely adapt better to a leg amputation than dogs with more intense lifestyles such as working or highly active dogs. Those dogs would likely not be the BEST candidates for surgical treatment of cancer.
What do we mean when we say that the tumor’s gross appearance is just the tip of the iceburg?
tumors have microscopic extensions, so you have to consider that what you see on the surface is only a glimpse into the the actual invasion that this tumor is realistically having
Why is palpation of the regional lymph nodes alone NOT a good means to determine if a cancer is metastatic or not?
What can you do in addition to palpation?
Some tumors, such as MCTs and oral melanomas, very commonly travel to the LN but don’t cause changes that you could observe on palpation alone.
You should always FNA the peripheral lymph nodes
What blood tests should you run prior to surgical cancer treatment?
Hematology – anemia, thrombocytopenia
biochemistry – liver, renal, hypoproteinemia
coagulation profile – DIC
BMBT – von willebrands disease
what are the 4 methods to diagnose a tumor?
- FNA
- Needle core biopsy
- incisional biopsy
- excisional biopsy
A pomeranian presents because the owners noticed a lump on the front leg. When you are examining this patient, you notice a few more lumps.
You decide to FNA them to hopefully get a diagnosis. You grab a 18g needle and sample from all of the lumps. You submit the samples to the lab for interpretation.
What went wrong here?
you used the same needle for multiple masses which means you contaminated your samples
Why would you choose BIOPSY over FNA? (3 reasons)
- if the tumor type/grade changes your choice of treatment
- if the tumor type/grade changes the extent of treatment (margins)
- if the tumor type/grade changes the owners willingness to treat
________ categorizes into epithelial, mesenchymal, or round cell and is diagnostic for some tumor types (such as MCT). However, is 13-35% of samples, the results are non-diagnostic.
fine needle aspirate
this test is good because it is cheap, no sedation is required, and it can help you r/o non-neoplastic diseases
What are 2 types of masses/tumors that you should ideally NEVER FNA?
- transitional cell carcinoma (tumor seeding into the abdominal cavity has been reported)
- adrenal masses (they are sensitive and can cause your pt to become unstable, ex. pheochromocytoma)
T/F: FNA provides tumor type and grade
false
If you FNA results are inconclusive, what diagnostic test is the next option?
Biopsy which will provide tumor type and grade, but requires sedation in most cases, requires careful consideration of the location and differentials.
What type of needle-core biopsy tool is used for soft tissues?
tru-cut
what type of needle-core biopsy tool is used for bone?
jamshidi
which type of biopsy (out of the 3) often only requires sedation and local anesthesia?
needle-core biopsy
What is the downside to needle-core biopsy?
they are still really small tissue samples that can be non-representative of the tumor or non-diagnostic.
So you should collect multiple samples to improve diagnostic accuracy.
T/F: oral tumor biopsy can be done with sedation and no local anesthetic
true
what are the 2 types of incisional biopsy tools?
- wedge
- punch
Why is PLANNING prior to incisional biopsy so important?
because if you need a definitive surgery, then you will need to be able to resect the entire biopsy scar WITH the tumor.
T/F: you should NOT do an incisional biopsy of an oral mass through the overlying lip
true. you should approach them intraorally.
why? because it will make your surgical resection more aggressive, require radiation after surgery, or render the tumor resection unreasonable.
Why is excisional biopsy so common but controversial?
They are diagnostic, but not therapeutic.
It is resecting the gross mass WITHOUT definitive margins, so it is preferred if you do an FNA/needle-core biopsy in order to PLAN a definitive surgical procedure to avoid leaving behind cancer.
T/F: the initial surgical procedure is the BEST chance for surgical cure of cancer
true
sometimes doing excisional biopsy first can be devastating
(ex. vaccine-assoc. sarcomas with excisional biopsy have 2 month MST whereas with curative intent surgery the MST is 16 months)
T/F: you should only consider doing an excisional biopsy in areas such as the distal limbs, where amputation could be performed if necessary.
false – you should only consider them in areas with sufficient soft tissue coverage like the lateral thorax, and NEVER areas like the distal limbs.
T/F: when doing an excisional biopsy, you should NOT take the fascial plane
true
you should leave it for revisions if they are needed.
What imaging modality options are available for local tumor imaging to assess tumor location, invasion into adj structures, and for surgical planning, as well as distant metastasis?
- radiographs
- ultrasound
- nuclear scintigraphy
- CT or MRI
- PET
Even though you should not SOLELY rely on lymph node palpation for staging and you must do an FNA or biopsy, you should still palpate the lymph nodes and assess what 3 things?
- symmetry
- enlargement
- degree of fixation
What are the 3 components of the World Health Organization T-N-M Staging System?
T – local tumor (T0-T4, 0 being no evidence of neoplasia, 4 being tumor invading other structures)
N – regional lymph node (N0-N3, 0 being no evidence of LN involvement, and 3 being a fixed node)
M – distant metastasis (M0-M1, 0 being no distant metastasis, 1 being metastasis with site specified)
Prior to performing surgery on a patient with cancer, you must determine if the goal of surgery is ___________ or ___________.
curative or palliative
this will depend on the tumor type, biological behavior, clinical staging, and the owners wishes
knowing the goal of surgery will help you determine your “surgical dose”
what are the 4 surgical doses?
- radical
- wide
- marginal
- intralesional or debulking
T/F: the most common mistake is being too aggressive with your surgical dose
false - using too low of a surgical dose is most common.
what 2 surgical doses are recommended for MOST solid tumors?
- radical
- wide
_________ resection is removal of a body part (ex. remove spleen due to splenic hemangiosarcoma)
radical resection
__________ resection is lateral and deep surgical margins to remove the COMPLETE tumor burden (gross and microscopic).
wide resection
the amount of tissue taken will depend on the tumor type and the biological behavior (based on histopath grade)
For the following tumors below, list the wide margin resection recommendations:
A. benign mass
B. grade 1 or 2 / low grade MCT
C. soft tissue sarcoma
D. intestinal tumor
E. feline injection site sarcoma
A. benign mass = 1 cm
B. grade 1 or 2 / l.g MCT = 2 cm
C. soft tissue sarcoma = 3 cm
D. intestinal tumor = 4-8 cm
E. feline injection site sarcoma = 5 cm or more
A _________ is any tissue that has resistance against tumor invasion
natural tissue barrier
examples include muscle fascia, joint capsules, tendons + sheaths, epineurium, cartilage, pleura, and peritoneum
T/F: with wide margin resections, you should remove at least 1 fascial plane
true
if feline injection site sarcoma, then removal of 2 is recommended.
_________ resection is INCOMPLETE excision of a tumor with residual microscopic disease
marginal
When would planned marginal resection be appropriate?
when the removal will be followed by adjuvant treatment such as radiation therapy
This is usually a good option for tumors on the distal extremities (MCTs or STSs) in order to preserve limb function.
You perform an excisional biopsy and you do not know the tumor type… You get the report back and you realize that this patient has an aggressive tumor. You realize that with excisional biopsy, you likely only removed the gross mass without getting definitive margins…
What are the 4 treatment options after an unplanned marginal resection like such?
- no treatment and just monitor for regrowth
- staging resection of surgical wound (take tissue from the scar and send for histo to see if you margins were good or not)
- wide resection of surgical wound
- adjuvant treatment (radiation)
__________ is INCOMPLETE resection of the tumor with residual GROSS disease.
debulking / intralesional surgery
this option is rarely acceptable because regrowth is rapid and the presence of the tumor makes adjunctive treatments like radiation LESS effective.
Why should you avoid directly grasping the tumor with your instruments during surgery?
leads to fragmentation and exfoliation of the tumor cells.
T/F: you should avoid drains and flaps in cancer surgeries
true
T/F: you should penetrate the tumor capsule in order to ensure complete removal
false – avoid penetrating the capsule or else you will exfoliate tumor cells.
What 4 tissues are considered “contaminated” in cancer surgeries?
- biopsy tracts
- SQ tissue undermined
- donor sites and incisions for flaps
- drain tracts
In what order should you resect tissue during cancer surgery?
benign / potentially normal tissue should be resected FIRST, then you can resect malignant masses.
what type of closure is preferred for cancer surgeries?
primary wound closure
T/F: you should ALWAYS submit resected tumors for histology.
true
even if you got a tentative diagnosis from the FNA or biopsy because those samples may not have been completely representative.
How much of the resected mass do you need to submit for histopathology?
the entire mass!
this is going to provide you with information for risk of local recurrence and metastasis, whether or not furthter tx is necessary, and the patients prognosis.
How do pathologists determine margin assessment?
they determine the absence of presence of neoplastic cells at the cut edge of the specimen
what is an example of a preventative cancer surgery?
OHE prior to 3rd heat cycle to reduce/eliminate risk of mammary, ovarian, and uterine tumors.
what is the purpose of palliative cancer surgery?
to alleviate clinical signs and improve QOL
