Oncology Biopsy and Surgery Flashcards
What is the leading natural cause of death in adult dogs
Cancer - 50% of dogs
Cats (2nd or 3rd) - 30-35% of cats
Why is there so much more cancer in pets?
Better pet health care = longer life
-vaccinations, preventative medicine
-nutrition
-leash laws, more pets indoors and/or supervised
-cancer is a disease of old age and we’re seeing more and more older pets
What is the association of environmental factors causing cancer in pets
weak associations between certain types of cancer and environmental influences
-K9 LSA and certain herbicides or urban environments
-K9 mesothelioma and asbestos
-Feline GI LSA and environmental tobacco smoke (ingest material on fur)
but in most cases, no strong associations
What cancer might make you want to investigate for potential environmental causes
K9 mesothelioma
-asbestos shown to increase cause
For the most part, food additives, lawn chemicals, pesticides, cosmic rays do not
meaningfully increase cancer risk
Why do we treat animals with cancer
Because we can!
-Cancer is a chronic disease (like diabetes, endocrine diseases, heart disease)
-Cancer is a disease we can sometimes cure
-Even in cases where cure is unlikely, there are many cancers where we can extend an excellent quality of life with treatment
T/F: needle aspiration cytology/ biopsy hastens the spread of the tumor
False-
-mast cell tumors could get inflammed but doesnt increase likelihood that it might spread
-not true in sarcoids
-splenic mass disruption potential (excess ion)
T/F: removing the primary tumor makes metastasis more likely
False- there is so much that goes into metastasis
Why do an FNA / Incisional Biopsy
helps plan your surgical approach (mast cell vs lipoma)
if already metastasis
What should you tell the owner if a tumor excision is used for diagnosis
forewarn owner that additional treatment/diagnostics may be necessary
What should you do if clients wont pay for histopathology after removing a tumor
incorporate into surgery fee- does not need to appear as line item on invoice/estimate
-if its worth removing, its worth submitting
What is the concern with submitting half of the tumor or “representative section”
cuts the info learned from the pathology report in half (margins not evaluable)
talk to your pathologist if you need to submit a very big sample
T/F: recurrent tumors are often much worse than first time tumors
True
-dont wait to submit for histo if it recurs
-dont wait to get aggressive or think about additional therapy if it recurs
Recurrent tumors are often much more likely to
-Grow back worse than first time tumors
-Grows back twice as fast
-Open and bleeding and painful
-Some tumors more likely to spread
Why do tumors get more aggressive and grow faster after incomplete resection
-You are selecting for cells that grow on the periphery around the mass and they are more successful at expanding (potentially higher metastatic rate)
What are 3 components of a pathology report
-Histotype
-Histologic grade (when applicable)
-Margins (must be interpreted taking into account tumor biology and aggressiveness of the surgery
How does incomplete margins affect mast cell tumor survival time
Incomplete is about 5x worse prognosis
Complete- median survival time of 54 months while incomplete is 11 months
18 month survival- complete: 69%
18 month survival-incomplete: 14%
will grow back and likely be more aggressive
What is palliative surgery
Increase quality of life, not necessarily quantitiy
ex:
-Ulcerated tumor with distant mets
-HSA/splenectomy
-OSA/amputation only
Weigh risk / benefit
Cytoreductive/debulking surgery
more common than planned
often just a big biopsy if no adjuvant treatment
Helps other modalities (if you can get down to microscopic)
-Benefits RT <hypoxic> dosimetry
-Benefits chemo (Amp with OSA)
-Benefits immunotherapy (melanoma)</hypoxic>
Avoid closing tumor to tumor
Animals most get the same cancer drugs that humans get except
-Lower doses
-Fewer drugs given together
Less than 1/3 of patients experience unpleasant side effects from chemotherapy
Less than _____ of patients experience unpleasant side effects from chemotherapy
1/3
5% or less experience a severe side effect but most are fixed in 24-72 hours
Risk of chemotherapy related fatality is less than 1 in 200
Should unpleasant side effects of chemotherapy drugs occur then
doses can be reduced, drugs can be substituted or additional medications dispensed
these changes are effective 90% of the time
Whats up with hair loss with chemotherapy
certain breeds of dogs (the so-called- non-shedding breeds) can lose a large amount of hair
-Nonpainful
-Non itchy
-Will regrow upon cessation of chemotherapy
-Dogs dont have the body imaging concerns
Why do most dogs not have hair loss with chemotherapy
chemotherapy drugs target rapidly dividing cells
only 1/3 of dog’s hair follicles are growing at a time
-areas that are shaved might take longer to grow back
but wont get bald (unless the non-shedding breeds as they have continuously growing hair like people do)
Almost all chemotherapy treatments is
outpatient - very unusual to have overnight treatment
most is half hour or less
Why is most chemotherapy outpatient procedures
-Most are bolus or short infusion
-Many protocols involve a series of treatments followed by a period of careful observation. Continuous indefinite chemotherapy is not usual
What should you tell owners if they say “I dont want my family and other pets to be contaminated”
Urine and feces pose a minimal risk to owners- few drugs are excreted for longer than 48-72 hours
practice common sense (wear gloves when handling urine or feces) is usually sufficient
normal daily interactions (grooming, playing, petting, handling food and water bowls) pose no real risk
What is a substantial risk with chemotherapy
Risks to the staff
need to have:
-dedicated waste stream
-closed containment system
-personal protective equipment
-spill kit with dedicated staff training
-USP800
What do you say to a client that says “Isnt she too old for treatment”
Most of the patients we treat with cancer are older pets
-stats regarding treatment effectiveness, survival and tolerability are usually generated in a population of older patients
Current quality of life and concurrent illness is more important *
Is chemotherapy an all-or-nothing proposition
For many tumor types, a spectrum of treatment options may be available, depending on owner availability and finances
Standard response criteria: Complete disappearance of all measurable disease
CR (Complete Response)
Standard response criteria:
>50% reduction in volume of all disease (>30% reduction in diameters) no new lesions
PR (Partial response)
Standard response criteria:
<50% reduction, <25% increase in volume of all disease
SD (stable disease)- can be a successful treatment option in some late-stage cancers
Standard response criteria:
>25% increase in volume (>20% increase in diameters)
PD (progressive disease)
Prednisone has a direct anti-tumor effect against what cancers
1) Lymphoma / lymphoid leukemia
2) Multiple myeloma/ other plasma cell tumors
3) Mast cell tumor
most others - not useful and potentially harmful for most other cancers
used NSAIDs or narcotics for pain, appetite stimulants, antiemetics
Prednisone can control clinical signs in what cancers
-Insulinoma (hyperglycemia)
-CNS tumors (edema and swelling leading to deficits)
-Paraneoplastic hypercalcemia
Prednisone for palliation can be useful for lymphoma, multiple myeloma, and mast cell tumors but ___________________
most others - not useful and potentially harmful for most other cancers
used NSAIDs or narcotics for pain, appetite stimulants, antiemetics
radiation therapy of incompletely resected tumors (STS, ISS, MCT SCC, perianal, CNS, dental)
Adjuvant radiation treatment
Radiation therapy can be used for the incomplete resection of which tumors
1) Soft tissue sarcoma (STS)
2) Injection site sarcoma (ISS)
3) Mast Cell Tumor (MCT)
4) Squamous cell tumor (SCC)
5) Perianal
6) CNS
7) Dental
radiation treatment to render tumor more amenable to surgery
neoadjuvant radiation therapy
radiation therapy is primary therapy to what tumors
1) Nasal
2) Some CNS
3) Dental
Uses of radiation therapy
1) Adjuvant to resection
2) Neoadjuvant to render tumors more amenable to surgery
3) Primary therapy for some tumors
4) Palliation of pain, swelling, etc (OSA, melanoma, certain LSA, thymoma)
T/F: animals receiving radiation therapy experience significant systemic illness (nausea, letargy)
False- RT is a local treatment modality
Systemic side effects are rare (anesthesia gives the side effects)
T/F: Animals receiving radiation therapy develop horrible radiation burns
True- varying degrees of local sun-burn like reaction can occur depending on the location, protocol, and individual
often fairly mild, usually starts last week of treatment, disappears within 2-4 weeks
Radiation therapy burns often disappear by
often fairly mild, usually starts last week of treatment, disappears within 2-4 weeks
Do animals receiving radiation therapy become radioactive
No- Standard radiation therapy in dogs is external beam, the radiation used is no different than regular x-rays, except higher energy
veterinary radiation therapy requires
1) multiple general anesthesias (or heavy sedations)
2) often some time in hospital (for practical reasons)
3) A lot of money
palliative is 1,500-6,000
curative: 6,500-15,000
What is the goal of a biopsy
to obtain a diagnostic sample while limiting morbidity, limiting potential extension and avoid interference with future treatments
Why might you biopsy in oncology
-appropriate prospective planning
-take advantage of several modalities
-Goldilocks treatment- not too little, not too much, just enough
-Limit morbidity
-hopefully improve overall ouctome
-and at all costs, avoid a whoops moment
How should you prepare for biopsy
1) Prospective planning
-Timing with imaging
-Placement of tract (tension lines, definitive Sx)
-Use simplest technique first
-FNA, large gauge FNA, needle core, incisional, excisional
2) Be aware and counsel owners on limitations/ error rate
3) Complications- hematoma, SSI, exophytic tumor growth
4) Diagnostic utility
would doing this test change what you do
diagnostic utility
What are the limitations of FNA cytology
No information on structure of tumor and therefore grade or benign/malignant
What is the diagnostic utility of FNA cytology
close to 100%
With deeper tumors, what can you use with FNA cytology
ultrasound for image guidance
FNA cytology is good for
round cell tumors, melanoma, and lipoma
Needle-core or Tru-Cut
14-15g (4-6 samples)
can use image guidance (US or CT)
if need quicker diagnosis can take tissue and make squash prep
What are the limitations of needle-core or True-cut
-size of tumor that is amenable
-May penetrate naive tissue or plane
-Risk to procedure (bleeding, air leak)
What do you need to consider when doing open biopsy
make the cut parallel to the tension lines- keeps options open for definitive and reduces risk of adding complexity
need flat pattern
make sure to keep clear, accurate surgical notes on where, how, which planes, etc.
Incisional biopsy is possible to do under
sedation and local anesthesia, depends on patient
When doing incisional biopsy, how should you make your cuts
deep and narrow - need an edge or normal and abnormal
you need basement membrane present
a group of abnormal cells that appear cancerous under a microscope but have not spread beyond where they first formed in the body, ie broken through the basement membrane
carcinoma in situ
you should absolutely never do an excisional biopsy on
injection site sarcoma (cat)
-do FNA instead
What are the criteria to do exicisional biopsy
1) Have curative intent resection option (bigger margins later)
2) High suspicion that it is benign
3) Palliation
For biopsy you should never
place a drain or tension relieving
When doing general biopsy, what needs to be included in the definitive plan
placement of tract
What should you do when doing bone biopsy
-image guidance (ultrasound)
follow same pattern- small gauge FNA first, larger needle, then core (Jamshidi), finally open
-post biopsy radiographs or fluoroscopy
Injection site sarcoma 3-2-1
mass is present, at least 3 months since the injection
swelling/mass is greater than 2cm
and has increased in size in the last 30 days
-do an FNA (never an incisional biopsy)
What is told in pathology examination
1) Neoplasia vs non-neoplasia
2) Benign vs malignant
3) Histotype or even subtype (IHC or ICC)
4) Grade*
5) Margins **
always ask if this makes sense
What should you so when the pathology report doesnt make sense
1) Call pathologist or email
-Resection
-IHC or other special stains
-Reaffirm the history, site, method, PE
-Second opinion or “relook”
2) Repeat biopsy
What are the roles of surgical oncologist
1) Surgeon
2) Long term management of patients
3) Clinical and translational research
4) Develops and supervises clinical trials
What are the 7 Halsted principles
1) Aseptic technique
2) Gentle tissue handling
3) Meticulous hemostasis
4) Preserve blood supply
5) Eliminate dead space
6) Accurate tissue apposition
7) Minimal tension
What are possible complications of doing biopsy
hematoma
SSI
exophytic tumor growth
From least invasive to invasive, rank the different biopsy principles
1) FNA
2) Large gauge FNA
3) Needle Core
4) Incisional
5) Excisional
What should you do prospectively for planning biopsy
1) Timing with imaging
2) Placement of tract (tension lines, definitive sx)
3) use simplest technique early
4) Be aware and consel owners on limitations/error rate
5) complications- hematoma, SSI, exophytic tumor growth
6) Diagnostic utility?
Why is hemostasis very important when doing biopsy
bleeding could potentially drag cancer cells deeper, expanding field
a bud of cancer cells that is separate from the main mass
present in some high grade tumors
satellite tumor
when the plane of resection is within normal tissues
higher chance for complete resection
Wide Resection
when plane of resection is within the tumor reactive zone
high risk of microsopic disease
Marginal Resection
What do you do if you cant get 2cm deep to the tumor on your resection because it is up against the first fascia plane
include that there is a barrier to tumor invasion
With marginal resection, there is a high risk for
microscopic disease
the tissue plane of dissection, which is continuous with what remains in wound bed
Surgical margin
You should never place a drain when you have a
planned marginal resection with high risk of local recurrence because there is a higher chance of microscopic disease and youre only going to expand your field
You should only consider a drain when
1) Wide and youve used a flap
2) You know there is a high risk for a seroma and a drain is the lesser of the two evils
If you are going to use a drain, what system is preferable
closed systems
-exit close to suture line with no need for tunneling
-exit point either in treatment field or close enough to be treated or removed
What tells you that you have a high risk for a seroma and should probably place a drain
Wide resection
1) Radiation therapy
2) High motion area
What is the risk of suturing deep layers of fat and using walking sutures when placing a drain
1) Painful
2) Risk taking out a vessel and the flap dies
What should you do when placing a drain after surgical resection
1) Closed systems
2) Do not suture deep layers of fat
3) Do not place walking sutures
What drain has the potential to extend your field?
Penrose drain
What factors influence the risk of seroma formation
1) Lymph node/ventral neck
2) High motion areas
3) Inguinal area
4) Pre-op radiation therapy
What should you tell the owner to do to prevent seroma formation
Strict rest
Ice packing
Surgisox (compression bandage)
There is no risk of drain/seroma if you have
1) Complete resection
2) Clean resection
3) Negative resection
but one drain or a badly placed one in an incomplete or dirty resection is trouble
With reconstruction, primary closure is always the first option and achievable in most cases but we should never let
complicated reconstruction limit our chances for local cure
Axial pattern flap
a flap is based on a known blood vessel, artery and vein
axial pattern flap is based on a named vessel
What should you never use in an unknown margin
releasing incisions- because it expands our treatment field
Should you do releasing incisions
NO- it expands treatment field
What should you consider when doing a flap
1) Always do with a wide resection
2) Change your gloves and instruments between flap and resection
3) Raise flap first, close donor site, then do resection
You should only consider a flap when doing
a wide resection (never marginal)
The quality of the pathology report is directly related to
quality of the speciment
Why do we use tissue inking
alert pathologist to an area of interest
1) Cut edge
2) Deep margin
can use different colors for different areas only to alert pathologist
What should you do to maintain tumor orientation when submitting a tumor
1) Ink cut edge and deep margins
2) Suture deep plane to skin to maintain orientation
3) Tend a picture
4) Send whole tumor
Where does changing gloves and instruments make a difference
1) Moving from site to site
2) Tumor ruptures in hand
3) High risk of seeding (ie urothelial carcinomas or thymoma)
4) Flap
Where does changing gloves and instrument not make a difference
1) Wide or marginal
2) Ruptured spleen
