Neoplasia treatment options Flashcards
What do we need to establish about neoplasia before devising a treatment plan?
Histopathology to assess cells for criteria of malignancy
Once we have determined it is malignant, we can grade it
Then assess neighbouring lymph nodes & distant tissues/organs to stage it
What are cancer grades
Grade describes appearance of cancer cells & surrounding tissue
Low grade tumours contain organised cells & look like relatively normal tissue
High grade tumour tissue is disorganised & cells look very abnormal
What are cancer stages
Describes:
- size of tumour
- How far it has spread from where it originated
How do we determine cancer stage?
To determine stage we need to:
- Palpate/sample local lymph nodes
- Image other sites in body to determinepresence of any metastases (usually thorax/abdomen)
What information do we need to make a targeted cancer treatment plan?
Full extent of cancer & if/where it has spread
How tumour is likely to behave clinically
How cancer is likely to progress
How do we make a treatment plan?
Talk to oncologist to get all options
- they can also help with giving more precise prognosis
Then talk owners through pros & cons of all available treatment options
Be mindful of:
- The fear of cancer
- Owners’ personal experience of cancer & its treatments
What are the possible treatment approaches?
- Monitor
- Treatment
a) Definitive cure
b) Remission- decrease or disappearance of signs of cancer, but cancer cells may still be present in body
c) Palliation- relieves clinical signs but doesn’t treat cancer itself - Euthanasia
What are some important considerations when choosing a treatment plan?
Cure vs palliation
Expected & potential side effects
Quality of life
Realistic expectation as to survival time
Describe monitoring as a cancer treatment approach
Watchful waiting
Can be appropriate where co-morbidities preclude further investigations or putative treatments
Must be satisfied that animal isn’t suffering & that owner can recognise if this changes
- Consider using pain scores or quality of life surveys
Not enough for owner to say they don’t want/can’t afford treatment
What are the possible treatment options for cancer?
Surgery
Chemotherapy
Radiotherapy
Others (cryotherapy, photodynamic therapy, emerging immunotherapies)
Multimodal approach used when appropriate
What are the possible aims of surgery?
Curative (surgery cures more cancer than any other treatment)
Cytoreduction/debulking
Management of oncological emergencies
Palliative
What are the uses of chemotherapy?
Primary treatment where surgery isn’t possible
- e.g. lymphoma, leukaemia
Adjunct treatment following surgery to ‘mop up’ any cancer cells left behind or micrometastases
Typically used to slow cancer progression, rarely curative (increase median survival time)
How does chemotherapy work?
Work by targeting rapidly dividing cells
Includes tumour cells but also normal cells in body => side effects
In particular:
- bone marrow
- fur/whiskers
- GIT
Generally better tolerated by animals than people
How can neutropenia (due to affect on bone marrow) as a side effect of chemotherapy be managed?
Monitor with complete blood count
Antibiotics indicated if severe or symptomatic
How can hair loss (fur & whiskers) as a side effect of chemotherapy be managed?
Supplementary essential fatty acids may help
Moisturising shampoos may prevent associated itching
How can gastroenteritis (due to affect on GIT) as a side effect of chemotherapy be managed?
Anti-emetics
Hospitalisation for IVFT if severe
Diarrhoea only needs treating if severe
- antibiotics +/- anti-diarrhoeals
What are some important chemotherapy considerations?
Must consider patient temperament
Patient will require multiple clinic visits
Many drugs need intravenous administration
Most protocols also require oral administration at home
What is radiotherapy?
Use of ionising radiation to treat solid tumours
What are the different methods of delivery of radiotherapy (classifications)?
External beam radiation (Teletherapy)(most common)
- Delivered (x-rays or gamma-rays)
Interstitial beam radiation (Brachytherapy)
- Implanted (gamma or beta-rays)
Systemic radiation therapy
- Injected (e.g. radioiodine)
How does radiotherapy work?
Radiation causes DNA damage in all exposed cells –> cell death
Focussed radiation delivered in small doses on regular basis minimises risk of carcinogenesis
Local therapy with no systemic effects
What are the possible aims of radiotherapy?
Curative treatment
- Adjunct following surgical removal of tumour to kill any microscopic cancer cells left behind (e.g. mast cell tumours)
- Sole treatment in some radiosensitive tumours that are inoperable or surgery not recommended (e.g. CNS tumours, anal sac tumours)
- Usually delivered in fractions 3x/week over 4 weeks
Palliative treatment (short-term/poor prognosis)
- Slowing growth & relieving clinical signs of inoperable tumours(e.g. nasal or CNS tumours)
- Pain relief(e.g. osteosarcomas)
Usually delivered 1x/week over 4 weeks (hypofractionated)
What are some important radiotherapy considerations?
Must consider patient temperament, co-morbidities & travelling practicalities
Only 6 centres in UK that deliver radiotherapy
Curative-intent radiotherapy requires 12 visits in 4 weeks
Each radiotherapy session is delivered under short general anaesthetic
Describe palliative care as a cancer treatment approach
Aim is to provide relief from pain & clinical signs of cancer, NOT treat cancer itself
e.g. analgesics, anti-emetics, appetite stimulants
Focus is on quality of life
Describe euthanasia as a cancer treatment approach
Considered a positive option once QoL can no longer be maintained
Support owners in their decision-making & provide tools to help them recognisewhen their pet has had ‘enough’
- Ask owner to think about 3 key things their pet enjoys doing- when they can no longer do them then it is reasonable to consider euthanasia
- Use quality of life surveys/scales
What clinical signs mean euthanasia should be considered?
Euthanasia should be considered when treatments don’t help or are no longer effective & animal is having difficulty with:
- Breathing
- Eating/drinking
- Elimination (either through incontinence or inability to move)
- Standing and walking
- Pain (owners may need help recognising this)
