Cancer treatment in animals
Card Set Information
Cancer treatment in animals
Vet Med - Module 12
What reasons might we use euthanasia to treat cancer?
Cancer too advanced at presentation, poor QOL
Concurrent disease, poor QOL
What reasons might we use palliative treatment to treat cancer?
Curative treatment not possible but good QOL
Curative treatment not acceptable to owner, but good QOL
What are the different treatment modalities we can offer for cancer?
What are the treatment options for a) primary tumour b) lymph nodes c) distant metastases?
a) surgical excision, radiotherapy, surgical excision/radiotherapy combined
b) surgical excision of node, radiotherapy of node, chemotherapy?
c) chemotherapy, immunotherapy
What is the best cure for local tumours?
Complete surgical excision
Why does tumour recurrence occur after surgery?
Inadequate removal of tumour due to poorly planned surgery
What are the aims of oncological surgery?
Cytoreductive surgery (with adjuvant)
What is definitive surgery?
When you remove all the tumour by using an appropriate surgical margin/technique
What are the three types of definitive surgery?
Local excision - narrow margins
Wide local excision - wider margins
Radical local excision - all tissues down to clean fascial planes
What type of surgery would be used for the following tumours: a) moderate invasion b) invasive tumour c) benign tumour?
a) wide local excision
b) radical local excision
c) local excision
What are the two methods of wound reconstruction?
Primary closure = direct apposition of skin e.g. free grafts
Secondary healing = granulating wound
What is cytoreductive surgery?
When you reduce the bulk of the tumour to microscopic disease and combine with radiotherapy or chemotherapy
When is adjuvant therapy started?
Post operatively - either immediately after the operation or after the wound has healed (10-14days)
What is radiotherapy?
The use of radiation to kill tumour cells
What type of cancer is radiotherapy used to treat?
Local treatment for primary malignant tumour which cannot be controlled by surgery
What are the aims of radiotherapy?
Definitive/curative - aims to kill off all tumour cells
Semi-definitive - aims to kill of significant bulk of tumour cells
Palliative - aims to improve QOL in short term
What are the advantages of radiotherapy?
Avoids removal of large volumes of tissue (aesthetically pleasing)
Preserves function of surrounding normal tissues - vital structures may limit surgery
What are the disadvantages of radiotherapy?
May not kill off all tumour cells (some are radio-resistant)
Can cause side effects
Can cause further development
How is radiotherapy delivered?
Teletherapy - external beam
Brachytherapy - radioisotope implantation, systemic administration
What are the acute side effects of radiotherapy?
Moist epidermal inflammation and keratitis
What are the delayed side effects of radiotherapy? How long can these take to manifest?
Necrosis, fibrosis, non-healing ulceration, CNS damage/demyelination, mutagenesis
Months to years
What is fractionation?
This is when you divide up the dose of radiotherapy into smaller doses over a period of time to reduce the side effects (as one big dose would be too much for the animal)
What tumours are treated using radiotherapy?
Radiosensitive tissues - lymphoma, carcinomas, mast cell tumours
Radioresistance tissues - rapidly growing sarcomas, osteosarcomas, brain and spinal cord
What is chemotherapy?
The use of cytotoxic drugs to kill tumour cells
What type of cancer is chemotherapy used to treat?
Systemic treatment for malignant tumours which have high metastatic potential or systemic treatment for chemosensitive malignant tumours which are multi centric or disseminated
What are the aims of chemotherapy?
To prolong life
To maintain good QOL
What is immunotherapy?
Modulation of the immune system to kill tumour cells
What type of cancer is immunotherapy used to treat?
Systemic treatment for malignant tumours which have high metastatic potential
What types of immunotherapy can be used?
Modulation of innate immunity
Modulation of specific immunity e.g. monoclonal antibodies targeted to tumour cells or other immune effector cells