Oncology Basics – Flashcards

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1. You can grade the tumour and form a prognosis, cytology can only identify some tumours. 2. You can determine if your margins were sufficient

A measure of how malignant it looks under the microscope !

Differ across the range of tumours. Typically they consider tumour size , if there is local lymph node involvement and the presence or absence of mestastases

A complete physical exam , appropriate lab info, radiographs ect is required in order that we may rule out disease , lymph node involvement, and other body tissues mets

Not all protocols are expensive. Estimates should be calculated for the first 1,3,6 months of treatment. They should include all costs drugs , administration , lab work, hospitalization . Major caveat problems are not uncommon and can lead to significant increases

The owner it provides high quality time and allows the owner to come to terms with the impending death

Median survival times should be given where available , but remember that distributions are often skewed and median values can be misleading

Bone tumours and mestastases to bone Spinal tumours Rapidly expanding solid tumours Peripheral nerve tumours

Owners need to be reassured if a tumour is not associated with pain. However pain can be managed and euthanasia is always an option

The treatment philosophy in companion animal oncology does not allow for suffering. 3 further issues arise under this heading. Vomiting: nausea can be preempted Inappetance: supportive nutrition Hair loss: not common except in some breeds with continuously growing coats poodles English sheepdogs schnauzers . Some cats may loose their whiskers

It is unreasonable to inflict suffering in a patient regardless of the potential long term benefits

Indicative of systemic spread and normally a poor prognostic sign

Are usually diffusely affected and diagnosis via fine needle aspirate should be possible

Systemic neoplasia such as lymphosarcoma , multiple myeloma

In tumours such as osteosarcoma

As palliative therapy when complete excision is not possible As an adjuvant after surgical excision to eradicate undetected mets , which are usually there at the time of diagnosis ; osteosarcoma , hemangiosarcoma, mammary adenoca,rcinoma Chemo sensitive tumours not suitable for excision Patients with generalised systemic disease

2-3 times higher than those administered to pets

because our ability to deal with toxicity issues is relatively poorly developed

A reduction in tumour mass by more than 50% but less than 100%

with other health problems which will affect the (a) overall prognosis (b) influence the dose and choice of agent

They have a significant effect on prognosis FELV don't do as well FIV do significantly worse

Licensed for use in dogs and cats. They can also cause harm to human beings if handled incorrectly. Informed consent must be sought from the owners

(1)Induction of complete and durable remission (2)while delaying the onset of multiple drug resistance and (3) morbidity associated with the treatment (toxicity) or the disease itself. (4) induce a second remission after relapse

1. Myelosuppression 2. Gastro intestinal signs

Doxorubicin Alkylating agents Cisplatin

Relatively resistant to chemotherapeutic agents. Conversely normal tissue with a high proportion of actively dividing cells or a short cell cycle time , are susceptible to destruction

Underdose can lead to tumour recurrence and there is a high likelihood of toxic effects in cases of overdose

Large animals tend to receive an overdose and small animals tend to be underdosed

Calculating Body surface area BSA . The maximum tolerable dose for a wide variety of agents has a better correlation with BSA than with weight.

BSA based dosing increases toxicosis in small dogs . In general we intend to overestimate BSA the magnitude of the error tends to increase as a function of weight. This does not explain why we see toxicosis in small dogs

For animals 15kg and less calculate the dose both ways and err on the side of caution. BSA remains an effective method for avoiding overdose in large animals

They have different mechanisms of action and different forms of toxicity. So you get greater efficacy and a lower incidence of adverse effects.

To synchronise tumour cell growth and then treat the synchronised surviving cells with a drug that acts at just the right stage of cell growth. Practically speaking the growth rates are so different that is is rarely achieved

5-Fluoroacil , an anti metabolite which causes severe neurotoxicity in the cat, characterised by acute blindness ataxia and hyperexcitability This is followed by opisthotonus convulsions dyspnoea and death Cisplatin leads to pulmonary oedema as result of damage to the pulmonary microvasculature

Vincristine and Doxorubicin

L-asparaginase and Doxorubicin. However all patients must be observed for at least 20 mins after completion of the injections with adrenalin on hand Doxorubicin reactions are characterised by pruritus , wheals, erythema , restlessness , vomiting or dyspnoea. If these are seen stop the infusion until they subside and then restart at a lower flow rate . The reaction is mediated by histamine release and if it persists should be treated with antihistamines , corticosteroids and IV fluids L Asparaginase reactions occur within 30 minutes of injection and are characterised by vomiting , diarrhoea , urticaria, dyspnoea,hypotension or collapse. Treatment is by antihistamines ,glucocorticoids and fluids. In severe case adrenalin may be required. L asparaginase is derived from E coli there may be immediate reactions or sensitivity increases with each injection Minimizing the likelihood of reaction : diphenhydramine ( benadryl )2mg/kg dogs 1mg/kg cats SC 30 minutes before infusion {some protocols include cimetidine 5mg/kg for dogs} Sodium dexaphospate 0.2mg/kg IV or IM

Venipuncture must be done by an experienced person. Cephalic and saphenous veins are reserved for purposes of drug infusion. Blood samples must be taken from the jugular veins. The catheter must go in clean at the first attempt. If a failed attempt is made then an alternate or proximal site must be used. Record which limb was used. Winged catheters are suitable for small volumes of drugs that are not likely to cause a tissue reaction Catheters should not be covered with bandage as it is important to be able to see the vein in case it blows .

1 Manage pain prophylactically 2 Prevent or control nausea and vomiting- metoclopramide or odansetron or the most effective. 3 Maintain adequate nutrition -no more than 12 hours anorexia without intervention , i.e tube feeding or small amounts high energy appetite stimulants ect 4. Employ strategys to minimize toxicity - ie preempt anaphylactic shock , dilute doxirubicin vincristine in saline and inject slowly , mix xxxx with food

Doxorubicin it is recommended to not exceed a total cumulative dose of 180 mg/m2 in dogs and 150-200 mg/m2 cats. Practically this means no more than 6 doses . The best test is biopsy from the right ventricular wall, which is very invasive and not available to most veterinarians . The best in practice is ECG (wide range of changes possible) and echocardiography ( reduced shortening fraction ) these measurements taken when therapy is initiated and then at a total dosage of 120mg/m2 and 180mg/m2 respectively. At each visit physical exam may detect a new murmur/dysrythmia. OVERT CLINICAL SIGNS are typical of congestive heart failure

Cats are more resistant but total cumulative doses exceeding 150-200mg/m2 can have clinical consequences

(1) dose reduction but this limits the good effects as well (2)Administering cardioprotectants but these lead to increased myelosuppression and reduced anti-tumour effect (3) There is some japanese research on other options involving bismuth which looked exciting about 5 years ago NEEDS UPDATING

Cats it is also sometimes seen in dogs . Cyclophosphamide and Doxorubicin often cause this problem. Anorexia occurs directly after Administration or a few days later when intestinal epithelial damage is at its height , it is usually transient and does not limit therapy.

An antiemetic such as odansetron . Butorphanol subcutaneous about 30 minutes earlier is widely used and effective

An abnormal mass of tissue . Tumours are classic signs of inflammation and can be benign and malignant (cancerous).

Cancer

(1) The process by which cancer spreads from the place at which it first arose as a primary tumour to distant locations in the body (2) The cancer resulting from the spread of a primary tumour

(1)A period during during which symptoms ate reduced ( partial) or disappear completely ( completely.

(1) appetite (2) Activity- amount,type, desire/willingness to do normal things (3) responsiveness to owner (4) Pain (5) Body weight

Mesenchymal tumours that may not exfoliate

1. Store in seperate container and fridge and label (2). Keep in zip lock bags (3).Pregnant women should NEVER handle them (4) WOMAN of child bearing age should use with caution , especially if considering coming pregnant. (5) NEVER recap needles in contact with agents (6) Absolutely NO eating or drinking in the chemotherapy preparation, administration or disposal areas (7) Use a SEPERATE pill counter tray (8) Use low traffic area when preparing drugs (9) Use an absorbable plastic pad (10) Wear gloves