Oncology

Question 1

By treating the cancer like any other a chronic disease,
seeking only to slow its development and control clinical signs, we allow the
animal to?

Answer 1

Maintain their previous quality of life, rather than trying to annihilate
all the cancer cells and experiencing unacceptable side effects.

Question 2

Cancer cells are cells that have escaped the body’s control and are?

Answer 2

Dividing and growing in an autonomous fashion.

Question 3

Tumour development occurs in stages. List them?

Answer 3

Initiation
Promotion
Progression

Question 4

What is the initiation stage of of tumour development?

Answer 4

The first step (due to one or more mutations) endows a somatic cell with
unlimited replication potential and/or other growth or survival advantages over
other cells

Question 5

What is the promotion stage of of tumour development?

Answer 5

The second step gives the cell ability to out compete neighbouring cells leading to expansion into a tumour.

Question 6

What is the Progression stage of of tumour development?

Answer 6

A third step provides the potential for malignancy by leading to invasion and
destruction of surrounding tissues and hence metastasis.

Question 7

Discuss surgery for cancer?

Answer 7

Surgery has been the primary treatment modality for cancers for hundreds of
years, and is the keystone in the management in nearly all oral tumours.
Care has to be taken however to resect the tumour and all of its’ “root
network,” and a CT scan is very useful in identifying occult extension of the
tumour. When performing a tumour resection, the surgeon should first
consider the resection needed to remove all of the cancer tissue before
considering how to reconstruct the deficit. Any surgery planned first by the
possible reconstruction is much more likely to fail. I would encourage the
surgeon to mark or ink the margins, and to indicate (for example with the use
of a staple or suture) where areas of concern for incomplete excision lie, the
pathologist can inspect these areas for incomplete excision in some detail.

Question 8

How does radiation therapy work?

Answer 8

Radiation Therapy
Radiation therapy (RT) is the second oldest treatment for cancer, and is also
a local therapy (treating one site in the body, rather than acting systemically).
RT seeks to damage cellular DNA, such that when the cell tries to divide it will
be unable to replicate its genetic material and undergo a “mitotic death.” The
sensitivity of a cancer to radiation depends on the tissue in question (some
tumours are much better able to repair radiation damage than others) and the
sheer bulk of the tumour. The simplest way of improving radiation sensitivity
is to surgically “debulk” the tumour since this will increase the proportion of
cells which are actively-dividing (and are therefore radio-sensitive), but
chemotherapy drugs (for example carboplatin) can also be used as “radiation sensitizers”) since these drugs will potentiate DNA damage and impede the
action of DNA-repair mechanisms.

Question 9

What are the two types of radiation therapy?

Answer 9

Definitive
Palliative

Question 10

What are definitive radiotherapy protocols?

Answer 10

Definitive protocols aim to cure the tumour, and involve hyperfractionation (giving lots of small doses of radiation;
typically 12-20 doses, often on at least three days a week for several weeks consecutively and reaching a total dose over 40Gy). Definitive treatments can cause acute side effects (for example mucositis of mucous membranes and
dry desquamation of skin). These adverse effects are related to the radiation
dose and dose interval. Although unpleasant, they are nearly always
manageable with appropriate supportive care and rapidly resolve when
treatment ceases.

Question 11

What do palliative radiotherapy protocols aim to do?

Answer 11

Palliative radiation protocols aim to control pain and inflammation associated
with the tumour and involve hypofractionation (typically giving 2-4 large doses
of radiation). It is important to know whether a proposed radiation treatment
will be palliative or definitive, since palliative protocols will have negligible anticancer effect, instead they seek to control pain and inflammation only. Such
protocols rarely cause acute toxicity, and are cheaper and easier to perform,
however the hypofractionation of radiation poses a much greater risk of
delayed radiation toxicity, usually occurring at least 6 months after RT is
administered (often at least 1 year later). Delayed toxicities typically involve
necrosis of late-responding tissues (for example bone, or nervous tissue), or
fibrosis (for example strictures in the gastrointestinal tract); these adverse
events are usually catastrophic and often result in euthanasia of the animal
concerned. Despite the potentially-devastating nature of late toxicities
however, palliative radiation protocols are very effective means of pain
control, and can be very safely used in true “hospice-care” cases where the
life-expectancy of the animal is less than 6 months.

Question 12

How do cytotoxic drugs work?

Answer 12

Cytotoxic drugs work similarly to RT in that they damage DNA such
that the cell is unable to replicate genetic material, or sometimes interfere with
the machinery of cell division directly.

Question 13

What are the two groups cytotoxic drugs are divided in to?

Answer 13

The cell-cycle specific drugs (where the only susceptible cells are those at a
specific point in the cell cycle), or cell-cycle non-specific drugs (where all cells are susceptible but the lethal effect is only realised when the cell tries to divide).

Question 14

Traditionally, cytotoxic drugs are given at the “maximum tolerated
dose” (MTD), and repeated as soon as possible after healthy tissues have
recovered. This kind of dosing works best where a large proportion of the
cancer cells are in the?

Answer 14

Cell cycle, thus is most effective in lymphoid
malignancies in dogs and cats.

Question 15

Why are oral tumours more difficult to treat with cytotoxic drugs?

Answer 15

Oral tumours (mostly) have a much smaller
proportion of cells within the cell cycle and so their response is typically much
less dramatic. Similar to RT, the chemo-responsiveness of a tumour can be
improved by surgically debulking so that a greater proportion of remaining
cancer cells will enter the cell-cycle and become sensitive to drugs.

Question 16

The most important example of anti-angiogenic therapy in
veterinary medicine is?

Answer 16

Metronomic chemotherapy and this has been shown to
be effective in some situations where MTD (maximum tolerated dose) chemotherapy is ineffective!

Question 17

Metronomic chemotherapy has subsequently been shown to control the
activity of?

Answer 17

T-regulatory lymphocytes (thus allowing a stronger anti-cancer
immune response) as well as the anti-angiogenic effect.

Question 18

Some of the tyrosine
kinase inhibitor drugs can also be used, off-license, to inhibit important cellsignalling pathways involved in angiogenesis. Give some examples?

Answer 18

For example:
toceranib, “Palladia” will inhibit the receptor for vascular endothelial growth factor, VEGF,
and masitinib, “Masivet” will inhibit the receptor for platelet-derived growth factor, PDGF, both important angiogenic ligands.

Question 19

List small molecule inhibitors
(SMIs) chemotherapy drugs?

Answer 19

toceranib, masitinib and many others

Question 20

All anticancer drugs affect cell division, aiming for greatest effect in the
tumour, but adverse effects are seen in tissues where cells are constantly
dividing, principally in the?

Answer 20

Gastrointestinal tract and in the bone marrow.
Thus, gastrointestinal upsets and bone marrow suppression can occur to a greater
or lesser degree with any medical anticancer treatment.

Question 21

Discuss hair changes in dogs and cats undergoing cancer treatment?

Answer 21

Alopecia is also a
problem in people but at the doses used in veterinary medicine this is seldom
a problem; cats commonly lose whiskers however and long-haired breeds of
dog often experience a change in coat quality. Poodles and other breeds who
need to be “stripped” will often go temporarily bald.

Question 22

How do nausea and vomiting happen with chemotherapy treatment?

Answer 22

First, certain drugs are
recognised by the brain’s chemoreceptor trigger zone as foreign poisons and trigger the vomit reflex while they are being given (for example carboplatin or
doxorubicin).
Secondly, all drugs will, to a less or greater degree, impede the
continuous replacement of the gastrointestinal lining, leading to malabsorption
and vomiting or diarrhoea 2-4 days after drug administration.

Question 23

How is haematology effected during chemotherapy?

Answer 23

Myelosuppression is usually evident first in the neutrophils (fastest half-life of
all cells in the bone marrow) and secondly in the platelets (second fastest
half-life). Since red blood cells have a long-life (60-80 days in cats, 80-120
days in dogs) and are replaced slowly, an anaemic animal (with normal
platelets and neutrophils) is unlikely to have become anaemic due to the
chemotherapy! Frustratingly, adequate numbers of neutrophils and platelets
are needed to stop opportunistic infection of the body by bacteria and
spontaneous haemorrhage respectively. Thus, during a chemotherapy
treatment we pay close attention to these cell lines for two reasons; first as a
sentinel of the level of myelosuppression we are causing and secondly to
make sure we are not endangering the patient’s life!

Question 24

What is cyclophosphamide?

Answer 24

Cyclophosphamide is an alkylating agent. Alkylating agents are oral oral
drugs (cyclophosphamide is also available as solution for injection) and are
cell cycle non-specific; they will alkylate the DNA of ALL cells, however the
lethal effect is only realised when the cells try to divide.

Question 25

What can happen after being on alkylating agents (cyclophosphamide) for a long time?

Answer 25

After being on any alkylating agent for a long time, permanent exhaustion of the bone marrow can be seen (usually manifest as thrombocytopaenia or neutropaenia). Cyclophosphamide is relatively sparing of platelets however, in contrast to other drugs of it’s class. Myelosuppression with certain drugs (for example melphalan and lomustine) can be particularly severe and unpredictable in cats.

Question 26

All alkylating agents cause minimal gastrointestinal effects and their oral nature makes them popular with owners (though not necessarily inexpensive!). Drug specific side-effects are important, for example:

Answer 26

cyclophosphamide can cause a debilititating sterile haemorrhagic cystitis; this will occur in 15-20% of dogs receiving cyclophosphamide in a metronomic fashion.

Question 27

What is metronomic therapy?

Answer 27

Metronomic therapy is a new type of chemotherapy in which anti-cancer drugs are administered in a lower dose than the maximum tolerated dose repetitively over a long period to treat cancers with fewer side effects.

Question 28

What is the only platinum agent in use?

Answer 28

Carboplatin is the only platinum agent in common use.

Question 29

How does the platinum agent carboplatin work?

Answer 29

It shares much in common with alkylating agents, having cell-cycle non-specific effects and potentially cumulative toxicity.

Question 30

What are the side effects of the platinum agent carboplatin?

Answer 30

It can cause acute nausea (mediated through effects on the chemoreceptor trigger zone) and can cause cumulative renal toxicity but is otherwise well tolerated.

Question 31

How is carboplatin (platinum agent) commonly delivered?

Answer 31

It is given as an intravenous infusion and is occasionally used as intracavitatory treatment for diffuse disease (for example carcinomatosis or mesothelioma)

Question 32

What is Doxorubicin and how does it work?

Answer 32

Doxorubicin has a number of mechanisms of action, both cell-cycle specific and non-specific. As such it is a broad-spectrum chemotherapy drug and used for a large number of cancers.

Question 33

What are common and more dangerous side effects of Doxorubicin?

Answer 33

It can cause cumulative cardiotoxicity in dogs, and cumulative nephrotoxicity in cats however it’s most important, dose limiting adverse effect is gastrointestinal toxicity. It is given by intravenous infusion, is a substrate for the MDR1 mutation and can cause acute nausea (as well as the devastating gastrointestinal toxicity resulting to the damage to the gastrointestinal epithelium). Doxorubicin is also the most potent vesicant of all chemotherapy drugs. If it is given subcutaneously then an antidote, “dexrazoxane” exists; prompt administration of dexrazoxane after a doxorubicin extravasation can often prevent amputation!

Question 34

Doxorubicin & anthracyclines e.g.

Answer 34

Mitoxantrone

Question 35

Epirubicin is a very similar drug to?

Answer 35

doxuribicin

Question 36

Mitoxantrone is like doxorubicin but is not considered to have what?

Answer 36

The canine cardiotoxic effect or the feline nephrotoxic effect. It is also not a vesicant drug and has even been used for intra-cavitatory chemotherapy. It is a much depleted range of mechanisms of action compared with doxorubicin however and so it should be considered much less hard-hitting

Question 37

Metronomic chemotherapy therapy consists of?

Answer 37

An NSAID and a low dose alkylating agent (like cyclophosphamide) both given orally, every day, at home.

Question 38

What does metronomic chemotherapy aim to do?

Answer 38

This type of treatment aims to inhibit angiogenesis and has immunomodulatory effects (helps promote anti-tumour immunity by depleting the T regulatory lymphocytes).

Question 39

Metronomic treatment is often attractive as it involves oral medications only, fewer blood tests, and the likelihood of side effects is generally low, however the most commonly-used metronomic drug is?

Answer 39

Cyclophosphamide and counter-intuitively cyclophosphamide is more likely to cause sterile haemorrhagic cystitis when given in a metronomic protocol than if given conventionally as a bolus.

Question 40

What is a Small molecule inhibitors?

Answer 40

Tyrosine kinase inhibitors

Question 41

Tyrosine kinase inhibitors (TKIs), can be used alone or added into either an injectable or a metronomic chemotherapy protocol to make the treatment more?

Answer 41

"hard hitting."

Question 42

How do Tyrosine kinase inhibitors (TKIs) act as more targeted therapy?

Answer 42

TKI drugs will not kill cancer cells, instead they will "switch off" their cell division. As such they are not a "poison" and represent a more targeted therapy.

Question 43

What are the two licensed Tyrosine kinase inhibitors (TKIs)?

Answer 43

Two tyrosine kinase inhibitors (TKIs), such as masitinib (Masivet) or toceranib (Palladia), have been licensed for use in dogs.

Question 44

What are the adverse affects of Tyrosine Kinase Inhibitors?

Answer 44

Adverse effects of TKIs which have been described include gastrointestinal toxicity (vomiting, diarrhoea, weight loss), neutropaenia, muscle cramping, epistaxis, hypertension, proteinuria, vascular leak syndrome and gastrointestinal bleeding. Although many adverse effects resolve when the drug is stopped or the dose reduced, some side effects (for example nephropathy) can be permanent.

Question 45

Metronomic chemotherapy or TKI therapy will aim for?

Answer 45

“Stable disease” where the cancer burden is kept at a stable size; over time the disease burden may slowly reduce if cancer cells are “normalized” and can die of senesence, however this effect is likely to be slow.

Question 46

Conventional, MTD (maximum tolerated dose) chemotherapy aims to kill cancer cells and reduce the disease burden. Thus, MTD is often used as a?

Answer 46

course, and stopped after the cancer burden has been reduced

Question 47

Metronomic and TKI therapy is designed as an ongoing course with no clear stopping point; stopping the therapy often means?

Answer 47

The cancer will start growing again.

Question 48

Oral tumours in dogs are characterised by?

Answer 48

locally-aggressive disease.

Question 49

Obtaining a good prognosis for your patient oral tumour hinges around?

Answer 49

Good local control of the primary tumour.

Question 50

What are the most common oral tumours, starting with most common?

Answer 50

Melanoma is the commonest, followed by squamous cell carcinoma, followed by fibrosarcoma and acanthomatous ameloblastoma. Osteosarcomas and round cell tumours occur rarely.

Question 51

What is the common diagnostic route for an oral tumour?

Answer 51

The diagnostic investigation is reasonably stereotyped, and involves haematology, serum biochemistry, urinalysis, imaging of the oral cavity and thorax, fine needle aspiration of the local lymph nodes (bilaterally) and biopsy of the mass. Record extent of lesion from physical examination Accurately record extent of mass on dental charts Take measurements for WHO Stage. The use of 3-dimensional imaging like CT is very useful since conventional radiography will not detect osteolysis unless 40% of the bone cortex has been destroyed.

Question 52

What are the the necessary margins and suggestions of sensitivity to different therapies of different oral tumours?

Answer 52

Question 53

Discuss oral melanomas?

Answer 53

Melanomas of the oral cavity in dogs are aggressive tumours, with a high rate of metastasis.

Question 54

What are the survival times for oral melanomas?

Answer 54

Survival times for oral melanomas treated with surgery alone range from 5-17 months, with 1 year survival rates 21-35%. If the local disease in the mouth is adequately addressed, most dogs with oral melanomas are later euthanased because of metastatic disease.

Question 55

What is the best treatment for oral melanomas?

Answer 55

As for all oral tumours, local therapy is the keystone in good melanoma management. Surgery is usually the first consideration but for locations which are not amenable to surgery melanomas respond well (80% response rate) to hypofractionated radiation therapy; often responses are complete (tumours almost disappearing). Following surgery there are two main options for systemic management of potential metastatic disease in canine melanoma: immunotherapy (Merial Melanoma Vaccine) and systemic drug therapy.

Question 56

How does the immunotherapy vaccine for melanomas work?

Answer 56

Immunotherapy involves treating with the Merial melanoma vaccine (Oncept). This is a DNA vaccine consisting of xenogeneic (human) tyrosinase DNA in a bacterial plasmid vector. The aim of the vaccine is to trigger an immune response against canine tyrosinase (expressed in melanocytes but not in other cells) and thus it represents a specific therapy. This vaccine is administered intradermally every 2 weeks for 4 treatments and then every 6 months thereafter. It has to be imported from the USA on a named patient basis, and is only available to veterinary oncology or internal medicine specialists currently. The vaccine appears to be safe with minimal adverse effects.

Question 57

What chemotherapy drugs may melanomas respond to?

Answer 57

In general, canine melanomas are poorly responsive to systemic drug therapy (as is the situation in human medicine), however MTD (maximum tolerated dose) chemotherapy with carboplatin, metronomic chemotherapy or targeted therapy with toceranib have been used with varying levels of success. Whichever therapy is chosen, monitoring would be performed by regular physical examination (particularly assessing the local tumour site and lymph nodes, as well as restaging with a CT scan or radiographs approximately every 3 months, to assess for the presence of any distant metastatic lesions.

Question 58

How do Canine Oral Squamous Cell Carcinomas behave?

Answer 58

Oral squamous cell carcinomas (SCCs) in dogs are usually very locally invasive, but the metastatic rate is in the order of 20-30%. When metastasis occurs, it is usually to the regional lymph nodes, or the lungs.

Question 59

Discuss the considerations/limitations of oral surgery of Canine Oral Squamous Cell Carcinomas?

Answer 59

Managing the local disease in the jaw can be difficult as surgical excision with adequate margins is extremely hard to achieve in the oral cavity. For this reason, surgery may be followed with radiation therapy to try to sterilise the surgical margins. If surgery is not possible, radiation therapy can be used in the gross disease setting; many SCCs of the dental arcades will respond well to radiation however not perhaps to the same extent as melanomas, and a hyperfractionated protocol is required (with consequent greater expense).

Question 60

In cases of oral canine squamous cell carcinoma that cannot/owners not keen to proceed with oral surgery and radiation what else can be done?

Answer 60

In cases which involve metastasis, or where margins of surgical excision are incomplete and adjunctive radiation therapy is not possible, adjunctive chemotherapy is usually offered. Chemotherapy can also be used palliatively in the absence of any local therapy, but any duration of response will sadly be short here. Carboplatin is probably the best-evidenced drug to use in this setting, and the client should understand that it is still not as effective for local control as surgery or radiation therapy. Metronomic chemotherapy may also be considered from a “first-principles” point of view. Responses have been observed to toceranib but responses are typically finite and it should be remembered that providing it works this is an ongoing treatment (not a course).

Question 61

How does the prognosis for mandibular and maxillary squamous cell carcinomas vary?

Answer 61

Dogs receiving appropriate local control of a mandibular squamous cell carcinoma (effected by appropriate surgery with or without radiation therapy) have achieved a good quality of life for an extended period (in the region of 2 years or more). Dogs with maxillary SCCs typically have shorter survival times, likely a reflection of the greater difficulty in achieving complete excision in this area.

Question 62

Discuss squamous cell carcinoma behaviour in areas that aren't the gingiva or buccal mucosa?

Answer 62

SCCs of the tonsil are much more aggressive than those associated with the gingiva or buccal mucosa. They are typically much more resistant to radiation therapy and have a very high metastatic rate (approximately 73%). This difference in aggression may not be directly related to the anatomic location; tonsillar SCCs have shown to be much more likely to be of higher grade than the SCCs of other areas in the mouth. Tongue-based SCCs are reported to be intermediate in their aggression between the gingival SCCs and the tonsillar SCCs.

Question 63

How does SCC of the tonsil treatment vary?

Answer 63

Due to the higher rate of metastasis for tonsillar SCCs, both local therapy (surgery and / or radiation therapy) and systemic chemotherapy are indicated for these tumours. Although earlier reports suggested very short survival times, we may now expect survival in the order of 6-10 months if both local and systemic therapy are given.

Question 64

All oral SCCs may be associated with what biochemical abnormality?

Answer 64

Hypercalcaemia.

Question 65

What is the behaviour of oral fibrosarcomas?

Answer 65

Oral fibrosarcomas are the most invasive oral tumour. Up to a third of cases metastasize (to local lymph nodes or lungs) but local disease is nearly always the cause of euthanasia. Complete resection of such a tumour will necessitate a radical rostral maxillectomy or mandibulectomy procedure, involving removal of the tumour and at least 3cm of healthy “margins.” Early reports of recurrence after this surgery stated a 40-60% local recurrence rate, more recent reports are of 20-25% recurrence. For this reason, surgery is best followed by adjunctive radiation therapy, even in the cases that are resected with clean margins.

Question 66

If surgery and radiation therapy are not possible for an oral fibrosarcoma are there any other options?

Answer 66

If surgery is not possible, there are no equally-effective alternatives. Oral fibrosarcomas are generally resistant to chemotherapy and only have a O.Davies www.improveinternational.com | 17 modest response to radiation therapy in the gross setting (although they are more responsive to radiation therapy when surgically “debulked” first).

Question 67

What are the previous other names for Acanthomatous Ameloblastomas?

Answer 67

Acanthomatous Ameloblastomas (AAs) are the tumours formerly known as acanthomatous epulides, adamantinomas, or basal cell carcinomas.

Question 68

What is the behaviour of Acanthomatous Ameloblastomas (AAs)?

Answer 68

These are benign tumours (not considered to have a metastatic risk), derived from the periodontal ligament. What sets them apart from the peripheral odontogenic fibromas (“POFs” previously referred to as fibromatous or ossifying epulides), is that AAs invade and destroy bone, POFs don’t.

Question 69

What is the treatment for Acanthomatous Ameloblastomas (AAs)?

Answer 69

Complete excision is all that is necessary to control the expansion of an AA, and is usually curative. If surgery is not possible then good responses have been reported to radiation therapy or intralesional bleomycin therapy (NB the author doesn’t recommend the use of intralesional cytotoxic drugs on health and safety grounds !).

Question 70

Why is oral surgery harder/has less successful outcomes in cats?

Answer 70

Feline oral tumours are even harder to treat than their canine counterparts, partly because smaller jaws and more delicate anatomy makes complete surgical resection difficult in many cases, and partly because cats often tolerate oral surgery, particularly mandibulectomy procedures, poorly. After oral surgeries, cats typically have to be fed by an oesophagostomy tube for at least 2-4 months, and in at least 12% cases, this is permanently. Maxillectomies are often much better tolerated than mandibulectomies due to the bracing effect of the upper jaw and nose; mandibulectomies are often associated with mandibular drift, malocclusion and self-traumatisation by lower teeth. Counselling the owner of a feline oral tumour patient is therefore much harder; whereas most dogs have excellent return to function long-term, the opposite is true with cats.

Question 70

What are most oral tumours in cats?

Answer 70

Most tumours are oral SCCs, with fibrosarcomas making up the remainder.

Question 71

How do feline oral squamous cell carcinomas generally behave?

Answer 71

Oral SCCs in cats are usually fast growing and locally invasive, carrying a poor prognosis. Interestingly, the feline oral SCCs are much less sensitive to radiation or drugs than their canine counterparts (they are more akin to the canine tonsillar SCCs than canine mandibular SCCs).

Question 72

Do feline oral SCC metastasise?

Answer 72

Although feline oral SCCs metastasize infrequently to regional lymph nodes, and rarely to distant sites, the morbidity associated with the local disease in the mouth often brings people to elect euthanasia on welfare grounds within months of diagnosis.

Question 73

How can feline oral SCC be managed?

Answer 73

Managing the local disease of a feline SCC is challenging because surgical excision with adequate margins cannot be achieved in the oral cavity. Thus, a combination of some or all of: surgery, radiation therapy, and chemotherapy represents the most common attempt for definitive therapy, the precise treatment being tailored to the specific details of each individual case. These treatment options rarely effect adequate long term local control however, and are limited by a very poor response to radiation therapy. The one-year survival rate is generally less than 10%, with a median survival time of about three to six months for most treatment regimes.

Question 74

Are oral tumours in cats radiation responsive?

Answer 74

Oral fibrosarcomas in cats share the radiation resistance of their canine counterparts, and of the feline oral SCC – in fact all oral tumours in cats are generally very radiation resistant.

Question 75

What is the prognosis for oral fibrosarcomas in cats?

Answer 75

The oral fibrosarcoma is extremely invasive and so complete resection is hard to achieve, local recurrence is common, and despite having a low metastatic rate, the prognosis is guarded to poor. Chemotherapy is frequently used, often in the gross disease setting but most cases I have treated have experienced a survival in the order of 4-8 months.

Question 76

For feline oral fibrosarcomas if chemotherapy was attempted what would be used?

Answer 76

Doxorubicin and carboplatin, or metronomic chemotherapy are the most popular choices for chemotherapy but insufficient cases have been treated to establish the optimal medical treatment.

Question 77

Before lomustine what should be checked?

Answer 77

The liver enzymes should be checked

Question 78

Before carboplatin what should be checked?

Answer 78

Renal function should be checked.

Question 79

If an extravasation occurs then treatment is often supportive but for doxorubicin extravasation (often the most severe!) an antidote, dexrazoxane exists; if given intravenously following a doxorubicin extravasation it can often?

Answer 79

Save the animal from the sloughing of tissue which would inevitably occur otherwise.

Question 80

What is the advice for owners handling animals on chemotherapy?

Answer 80

First, pregnant or nursing mothers should not handle chemotherapy drugs or waste from the animal. Faeces should be double-bagged before disposal, and gloves should be worn to empty litter trays or clean vomit. If possible the animal should be restricted to a small area of the garden to defaecate and if urine or faeces are passed on a patio or hard floor, bleach should be used to clean up afterwards (bleach is expected to denature the drugs). If owners are to administer oral medications to their animals, the veterinary staff should make sure that they are fully competent in doing so, and that the animal is not expected to prove challenging to medicate. All oral medication should be handled with gloves and considerable care should be taken to make sure that pills or tablets don’t get crushed or split.

Question 81

What are the acute adverse side effects of radiotherapy?

Answer 81

Question 82

What are the late adverse side effects of radiotherapy?

Answer 82

Question 83

What are the benefits of metronomic chemotherapy?

Answer 83

Question 84

Summarise the 3 types of medical cancer treatment?

Answer 84

1. Conventional “MTD” chemotherapy * Kills dividing cancer cells * Usually a discrete course of treatment * Dose intervals dictated by Eme for healthy Essues to recover 2. AnEangiogenic therapy e.g. metronomic chemotherapy * Alters the microenvironment of the tumour (metronomic chemotherapy also alters the immune response to promote anE tumour immunity) * No defined stopping point * Intervals between doses are rarely needed 3. Small molecule inhibiEon e.g. MasiEnib (Masivet) or Toceranib (Palladia) * Interrupt specific molecular interacEons which are occurring in an uncontrolled way to cause uncontrolled cell growth and proliferaEon. * No defined stopping point * Intervals between doses are rarely needed

Question 85

Summarise treatment of cancer:

Answer 85

*Consider natural selection & survival of the fittest to understand cancer behaviour. *Read the pathological descriptions in pathology reports to predict tumour behaviour from first principles. *Treat pathology reports like all other diagnostic tests! *Onco-surgery is a specialised discipline; although neoadjunctive chemotherapy can shrink a tumour, the most malignant cells are the most peripheral! *Palliative & definitive RT protocols are available, and radiation response is dictated by the tissue in question and the size of the mass. *Medical therapy should be considered for metastatic or systemic disease; conventional MTD chemotherapy may not be optimal for solid tumours and use of anti-angiogenic techniques and small molecule inhibitors have found some support. *The optimal medical treatment for a lot of solid tumours has yet to be established but it may involve combination of MTD, antiangiogenic or small molecule treatments. *Manage cancer as you would any chronic disease!

Question 86

How do you WHO stage a mass?

Answer 86

Question 87

What is a Canine Peripheral Odontogenic Fibroma?

Answer 87

Surgical resection without bone removal – 0-17% local recurrence Radiation therapy: 3 year disease control in 86%

Question 88

Summarise oral tumours?

Answer 88

Surgical resection without bone removal – 0-17% local recurrence Radiation therapy: 3 year disease control in 86%

Question 89

What are risk factors for feline SCCs?

Answer 89

*Feline Oral SCC Strong environmental component in carcinogenesis *Risk increases by 4 times with use of flea collars *Exposure to household tobacco smoke increases risk by 2x – NB difficult to measure “true” smoke exposure *High intake of canned food ? Especially tuna?

Question 90

Summarise feline oral tumours?

Answer 90

*Most oral tumours in cats have a small metastatic risk. *The same diagnostic and therapeutic principles are true in cats as for dogs however survival times are usually not as good owing to SCCs being extremely aggressive and poorly tractable with RT or chemo. *Cats tolerate maxillectomy better than mandibulectomy

Question 91

What are the common side effects of medical anti-cancer therapy?

Answer 91

Question 92

Summarise cyclophosphamide?

Answer 92

Question 93

Summarise chlorambucil?

Answer 93

Question 94

Summarise Doxorubicin?

Answer 94

Question 95

Summarise carboplatin?

Answer 95