Oncology Flashcards
what is surgery oncology
patient centered approach to tumor mangement
what are the limits we need to be aware of
-PE (knowledge of regional anatomy)
-familiarity with disease process/tumour biology
-effectiveness and limits of surgical techniques
what do you have to be on the same page with the owners about related to goals
-many pts will have very advanced disease
-know palliation vs cure. this is very important
what is staging vs grading
staging = extent of disease
grading = determination of tumor behaviour
what is staging based on
based mostly on pre-op evaluation
-lymph nodes, lungs, other
what is grading based on
-requires histopath
-CANNOT be determined on cytology
-associated with propensity to spread elsewhere vs local aggressiveness
four basic principles of oncology
-what is it
-where is it
-how bad is it
-what to do about it
cytology vs histopath
cytology
-examines individual cells
-obtained via FNA
histopath
-examines tissue sections
-requires biopsy
what can cytology help determine
cancer vs not cancer
cancer; round cell tumor, sarcoma, carcinoma
not cancer; inflammation, abscess, seroma
what is one thing to avoid when doing a FNA
avoid blood contamination
what is the first tip for collection for a FNA
-make lots of slides; at least 5, do 2-3 separate collections in different areas
-pass needle through 2/3 thickness
why do you want to avoid the center of a mass when doing a FNA
because the centre is usually necrotic so you wouldnt be able to tell what is going on if that is the part you sample
what is the second tip for FNA collection
avoid blood dilution!
-dont use a large bore needle
-dont over aspirate
-imprints; blot blood off of tissue first
what should we do with all cutaneous and subcutaneous masses
they should be aspirated and body map should be done
six types of mast cells tumors
-lymphoma (LSA)
-mast cell tumor (MCT)
-histiocytoma
-plasma cell tumor
-melanoma
-transmissible venereal tumor (TVT)
do round cell tumors exfoliate well
usually. solid tissue aspirates usually highly cellular. neoplastic cells often are in effusions
what is an example of an epithelial tumor
carcinoma
do epithelial tumors exfoliate well
usually. aspirates of solid tissue usually exfoliate well. depends when there are effusions
how specific of a diagnosis can you get with epithelial tumors
benign vs malignant
sometimes specific cell type
what is an example of a mesenchymal tumor
sarcoma
do mesenchymal tumors exfoliate well
they often exfoliate poorly.
-solid tissue aspirate may be cellular
-aggressive tumors exfoliate better
-virtually never exfoliate in effusions
how specific can you get with mesenchymal tumor dx
-exact tumor type typically requires histo
-can be a very difficult cytologic dx
pros vs cons of biopsy
pros
-better planning (first change at sx is best chance)
-definitive dx enables pre-op radiation
cons
-two procedures. progression while waiting to do definitive sx
-cost
-increased risk fo local recurrence if the entire biopsy tract isnt removed during surgery
when should we biopsy
-if you cant get a definitive answer from cytology alone
-if the grade of the tumor would affect the treatment elected (particularly important in areas where a wide surgical margin cant be easily obtained)
when should we not biopsy
-if you cant get a definitive answer off cytology alone and surgical approach wouldnt be affected by histopath
-if you are unsure of sx approach and biopsy may compromise curative intent procedure
two types of biopsies
-incisional
-excisional
what is an incisional vs excisional biopsy
incisional = taking a piece of the tumor to get a dx
excisional = removing the entire tumor with a narrow margin of normal tissue (leave the fascial plane intact)
advantages of incisional biopsies
-wont change definitive sx margins
-doesnt decrease the chance of a clean cut (if taken properly)
limitations of incisional biopsies
second sx required in all instances (including benign dz)
advantages of excisional biopsies
potentially curative with benign dz
limitations of excisional biopsies
-increases re-cut margin if malignant
-can decrease chances of clean cut
what is always the likeliest cure
first cut!
what type of biopsy should we do
incisional biopsy should be performed rather than excisional biopsy in all cases EXCEPT
1. very small cutaneous masses <1cm
2. unable to get larger margin regardless of surgery (splenectomy)
what needs to happen before performing biopsy
need a cytology first (esp with excisional)
methods for incisional biopsies
-wedge/keyes punch
-core/tru cut needle biopsy
methods for excisional biopsies
-surgical excision
-keyes punch
benefits vs limitations of wedge/keyes punch
benefit = large sample
limitation = generally requires general anesthesia
benefits vs limitations of core/tru-cut needle biopsies
benefit = can be done under sedation
limitations = small samples
when would you want to use a core/tru cut needle biopsy
when you have large tumors that would be difficult to get deep enough to obtain a sample
how to determine extent of the disease
-local disease
-locoregional metastasis
-distant metastasis
why is it important to define the stage of disease (4)
-aids in planning treatment
-allows more accurate prognosis
-assists in evaluation of pt response to therapy
-allows communication between clinicians
what do we do to determine staging
-PE
-labwork (CBC, biochem)
what extra tests to do when there is suscept distant metastasis (3)
thoracic rads, abdominal u/s, bone marrow
what extra tests to do when there is suscept locoregional metastasis (1)
lymph node eval
how do we assess local lymph nodes
identify draining nodes (looking for the right ones is important), cytology, histopath
tests to evaluate lungs
rads, CT
tests to evaluate abdomen
u/s
cytology
what is prognosis based on
tumor type, grade and stage
when does prognosis need to be considered and why
-before and after surgery
-will impact approach pre-op and may change based on histopath results post op
what are the many factors prognosis depends on (2)
-surgical vs medical management
-are the owners prepared to do the follow up (chemo)
four current therapy options for cancer in pets
surgery, radiation, chemo, investigational
local vs systemic treatment modalities
local
-surgery, radiation
systemic
-chemo, radiation, immunotherapy
what are some surgical considerations you need to worry about (4)
-minimize handling of the tumor
-ligate the venous side first
-change gloves, instruments and towels
-lavage (dilution)
what factors to think about when planning your excision
-what is your goal
-clip wide
-positioning; consider tension lines and motion areas
what is a pseudocapsule
compressed neoplastic cells encapsulating the tumor
what is the reactive zone
reactive host cells surrounding the tumor
what is a satellite tumor
neoplastic cells outside the pseudocapsule
what is skip metastasis
rare but its when neoplastic cells are distant to the tumor (in the same compartment)
types of surgical excisions (4)
-intracapsular
-marginal
-wide
-radical
what type of surgical excisions have curative intent
-wide
-radical
when should intracapsular excisions be performed and why
only ever with benign disease because it leaves gross disease behind (ie lipoma, bone cyst, etc)
do wide excisions address skip metastasis
no
what type of margins do we need
need to consider both deep and lateral to ensure we are getting proper margins
lateral margins; units, based on what, size
-units = metric
-based on = distance from the peripheral edge of the tumour
-size = 1-3cm depending on the tumour type
fascial planes; barrier to what
barrier to tumor penetration
tumor should be moveable above it
what is the most common reason for a dirty margin
lack of fascial plane
what are some examples of fascial planes
-fascia
-tendon/ligament
-muscle
-bone
what type of excision can improve cosmesis? when is it beneficial?
elliptical excision
beneficial in instances of palliation
when is elliptical excision not recommended
-extends cancer field
-not recommended for malignant lesions
when should you not use a drain and why
drains can increase the cancer field. so avoid is possible and if necessary locate in an area that can easily be resected or included in RT field
what does radical surgery prevent
prevents any chance of local recurrence
-amputation
-splenectomy
-lung lobectomy
what should we consider when submitting samples for testing? (3)
-conscise, accurate hx
-maintain proper orientation of tissue (provide a drawing or pics, place a suture if needed for orientation)
-ink your lateral and deep margins
things to look for to determine grade
-mitotic index (# per 10 high power fields or pHPF in lymphoma)
-anisokaryosis and other criteria of malignancy
-necrosis
-features unique to that tumor type
what does clean vs dirty margins mean
clean = no tumour cells in contact with the margins
dirty = tumour cells in contact with the margins
does histologically clean equal clinically clean margin
no
when do you recommend radiation therapy
-expectation based on surgery
-consequence of local recurrence
