Introduction to veterinary oncology Flashcards
Is cancer a major cause of death in animals?
Yes - animals are living longer
USA study - 45% dogs >10 years old died of cancer
What are the major DDx for cnacer?
Inflammatory lesions - abscess, granuloma
Haematoma
Seroma
Cyst
What history/clinical evidence should you consider when deciding if a mass is cancer or not?
How long has it been present?
Is it growing and how rapidly?
Is it hot, erythematous or painful? (might indicate inflammatory lesion but could still be neoplasia)
Solid or fluid filled? (fluid could indicate abscess, seroma, haematoma, cysts - but could still be a tumour with necrotic centre)
Is it well-defined or ill-defined? Is it fixed to underlying tissues? (ill-defined lesion or fixation might indicate infiltrative growth or tumour)
What is the best way to go about making a diagnosis?
TAKE SAMPLES!
Cytology - FNA
Histopathology
What information does cytology provide you?
- Quick, cheap, easy
- Usually can distinguish inflammatory vs. neoplastic (inflammatory contains neutrophils or mixed cell population. Neoplastic lesions have one predominant cell type).
- Cell type and morphology (helps determine if benign or malignant)
- Useful to analyse effusions and BM
What information does cytology NOT provide you with? 4
Tissue architecture
Mitotic index
Invasion - vasculature/lymphatics
Tumour grade
How do you perform histopathology?
Requires biopsy under GA or sedation
Incisional, excisional, tru-cut, Jamshdi or trephine biopsy
How does histopathology tell you?
Gold standard for Dx
Differentiate inflammatory and neoplastic
Cell type and morphology
AND:
Tissue architecture (is it disrupted?)
mitotic index
invasion - vasculature/lymphatics/surrounding tissues
degree of necrosis
These features help decide if benign/malignant and sometimes assign a grade.
What should you do if a lesion is neoplastic?
- Determine cell/tissue of origin (epithelial, mesenchymal or round cell) - cytology or histopathology
- Special stains/IHC or additional techniques (flow cytometry) are sometimes required to make/refine Dx (e.g. to determine whether a lymphoma is a BC or TC origin)
Why is a definitive diagnosis essential?
Different tumour types have different biological behaviour and have different treatments.
Are lipomas and meningiomas benign or malignant?
Both benign
What is a tumour grade?
Assigned by pathologist
Helps predict behaviour of certain tumour types (MCT and STS)
Involves assessment of: mitotic index degree of cellularl differentiation invasion - surrounding tissues/BVs/ lymphatics Amount of necrosis etc
Categorised as low, intermediate or high
When are numbers assigned to tumour grade?
Some specific cancers:
Patnaik grading system - MCT (1= low to 3=high)
Kiupel grading system (new) - MCT - 2 categories (low and high)
Why is grading important?
Can affect treatment plan and prognosis
Important for communication
What is clinical staging?
Performed after cancer Dx = assesses the extent of disease in patient, performed by clinician ASSESSMENT OF: primary tumour drainage LNs screening for distant metastatic disease
TNM system often used (T= primary tumour, N = node, M = distant metastasis)
What is assessed in the T part of the TNM system?
T = primary tumour Size Mobility Relationship to surrounding tissues Presence/absence of ulceration/erythema
Physical palpation in many cases but may require imaging or endoscopy assessment
Sometimes the T,N and M are given a numerical or alphabetical suffix reflecting the extent of the involvement.
What is assessed in the N part of the TNM system?
Assess drainage LNs for: size mobility relationship to surrounding tissues (mobile/fixed) texture consistency
Imaging might be required (internal LNs)
FNA (or biopsy) frequently used to assess if LN metastasis is present or not (nodes can be normal size yet affected by metastasis. Enalarged nodes can be metastatic or hyperplastic).
What is assessed in the M part of the TNM system?
History and PE give clues
Usually assessed via imaging
Lungs most common site for distant metastases (SA) –> thoracic radiographs (ideally inflated, 3-views) or CT (this is more sensitive for detecting metastases)
Other sites can be important - liver, spleen, kidneys, heart, skin, bones, CNS
FNA/biopsy maybe needed to confirm metastasis
Outline primary tumour classification (T)
T1 = 5cm diameter
Outline regional node classification (N)
N0 = histologic or cytologic - no metastasis N1 = histologic or cytologic - metastasis present
Outline distant metastasis classification (M)
M0 = no distant metastasis present M1 = distant metastasis present
When is the TNM classification not used?
For systemic or multicentric diseases - e..g. lymphoma present in a disseminated form and the TNM system is not appropriate. Lymphoma is staged according to the organ systems involved.
Outline the WHO system for staging canine lymphoma
1 = involvement limited to a single node or lymphoid tissue in a single organ (excluding BM)
2= involvement of more than one LN in a regional area (+/- tonsils)
3= generalised LN involvement (both sides of diaphragm)
4 = liver and/or spleen involvement (+/- stage 3)
5 = manifestation in the blood and involvement of BM and/or other organ systems (stages 1-4)
Differentiate tumour grade and tumour stage.
GRADE - describes how abnormal the tumour cells and tiissue look under the microscope. Indicative of ho wquickly a timour is likely to grow and spread
STAGE - refers to the size and/or extent/reach of the original/primary tumour and whether or not cancer cells have spread in the body
Why do paraneoplastic syndromes arise?
They are the result of tumours that secrete a: hormone hormone-like substance enzyme cytokine OR via immune-mediated mechanisms
What 4 baseline tests can you use to assess the cancer patient?
Haematology/CBC
Biochemistry
Urinalysis
Coagulation parameters - when inicated
Why do haematology/CBC?
Assess general health status Essential as a baseline prior to starting chemo since many of these drugs are myelosuppressive Assess RBC and WBC #s and morphology: - anaemia - cytopaenias - abnormal cells
Why run a biochemistry profile?
General health status
Assess organ damage/function (e.g. prior to GA, chemo)
Important to look for paraneoplastic effect of tumour
Give some examples of paraneoplastic effects
Hypercalcaemia
Hypoglycaemia
Hyperglobulinaemia
Why might you get hypercalcaemia with cancer?
Tumour production of PTH-RP
Examples = lymphoma, myeloma, lymphoid leukaemia, anal sac adenocarcimoma, other cacinomas, thymoma
Untreated –> renal damage
Can also occur with increased PTH (parathyroid adenoma)
Why might you get hypoglycemia with cancer?
due to insulin secretion (insulinoma) or insulin-like growth factors (hepatic tumours, smooth muscle tumours)
Why might you get hyperglobulinaemia with a tumour?
due to excessive Ab production (e.g. myeloma and occasionally with lymphomas)
Why do a urinalysis?
Baseline screening for underlying renal problems or other diseases
When do you run coagulation parameters?
tumours can cause abnormalities in coagulation - both hypo and hypercoagulability
Thrombocytopaenia
Manual platelet counts and coagulation tests (PT, PTT, thromboelastography) might be indicated - e.g. if patient is showing bleeding tendencies
Give some paraneoplastic effects 10
Hypercalcaemia Hypoglycaemia Hyperviscosity (with hyperglubulinaemia, polycythemia) Gastric ulceration/vomiting Endocrine problems Pyrexia Immune-mediated diseases Hypertrophic osteopathy Dermatologic manifestations Cancer cachexia
Clinical signs - paraneoplastic hypercalcaemia
PD/PU depression anorexia weakness bradycardia
Clinical signs - paraneoplastic hypoglycaemia
weakness
collapse
seizures
Clinical signs - paraneoplastic hyperviscosity (with hyperglubulinaemia, polycythemia)
neuro signs
seizures
retinal detachment
Clinical signs - paraneoplastic endocrine problems
HAC (pit or adrenal) Hyper/hypo-thyroidism with thyroid neoplasia acromegaly (excess IGF-1, adenoma cats) feminisation (sertoli cell tumour) hypertension (phaeochromocytoma) hypercalcaemia (excess PTH or PTH-RP) hypoglycaemia
Clinical signs - paraneoplastic immune-mediated diseases
Rare: IMH, IMT, polyarthritis, polymyositis, MG (thymoma)
Clinical signs - paraneoplastic hypertrophic osteopathy
lameness and swelling of long bones - periosteal new bone on shafts of long bones associated with intrathoracic masses. Mechanism unknwon
Clinical signs - paraneoplastic dermatologic manifestations
endocrine or immune-mediated
Define polycythaemia
= erythrocytosis, means having a high concentration of red blood cells in your blood.
What factors should be discussed with owners?
All of the treatment options Owner expectations and goals of treatment Importance of QoL Psychological factors Patient temparament Patient general health status Possible complications and adverse effects of treatments Cost Time/logistics/number of visits Multiple GAs Prognosis
Outline cancer treatment options
MOST COMMON:
Surgery
Radiation
Chemotherapy/cytotoxic drug therapy
OTHER:
Molecular targeted drug therapy (TKI)
Anti-angiogenic therapy (metronomic, continuous low-dose chemo)
Immunotherapy (melanoma DNA vaccine)
Others - photodynamic therapy, electrochemotherapy, bisphosphonates
When is surgery used?
many tumour types
carcinomas, sarcomas, MCT
sole or combination
can be curative
When is radiation used?
primary treatment (e.f. for nasal tumours or for localised radiosensitive, non-resectable tumours)
frequently used as an adjunctive therapy
also neo-adjuvant therapy (to shrink tumour)
When is chemotherapy indicated?
systemic disease (lymphoma, leukaemia, myeloma, systemic mast cell disease, disseminated histiocytic sarcoma) Highly metastatic tumours - used as an adjunctive treatment, following surgical removal of the primary tumour (HSA, OSA, high grade STS) Sometimes used following incomplete resection or to treat non-resectable chomsensitive tumours or to shrink a tumour prior to surgery (non-adjuvant chemotherapy)
What supportive care can you give to the cancer patient?
TRY TO ANTICPICATE/PREVENT adverse effects
Nutrition
Hydration
GIT problems/anorexia - consider gut protectants (H2 blockers, sucralfate, omeprazole), anti-emetics (maropitant, odansetron), appetite stimulants (cyproheptadine, mirtazepine)
ABs - if neutropenic (due to disease or chemo)
Analgesia - short and long term (NSAIDs, opiods - tramadol, buprenorphine), other (gabapentin)
Physio
Why are chemotherapy drugs a health and saftey risk?
carcinogenic
mutagenic
teratogenic
How should injectable chemo drugs be drawn?
ideally they should be reconstituted or drwan into syringes in a cytotoxic safety cabinet (biological class 2 or 3). The Phaseal system is useful in a practice situation - allows safe preparation and a closed administration system. Pre-prepared doses can also be bought (Chemopet).
Luer-locking syringes should be used
How long should you be careful about a chemo animal?
Residues of cytoxic drugs will be present in body fluids/excreta of dogs and cats for several days after treatment (Vincristine in urine for 3 days, vinblastine for 7 dyas and doxorubicin for up to 21 days)
