Oncology Flashcards Preview

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Flashcards in Oncology Deck (299)
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1
Q

what is cancer?

A

diverse range of conditions with a common theme of persistent, pointless proliferation of host cells often to the detriment of the host

2
Q

what is the spectrum of behaviour that can be displayed by tumors?

A

truly benign
highly malignant
local characteristics of malignancy but do not metastasise

3
Q

what are the 6 features necessary for the development of cancer?

A

evading apoptosis
self-sufficiency in growth signals (not required from the body)
insensitive to anti-growth signals
tissue invasion and metastasis
limitless reproductive potential (continuous growth)
sustained angiogenesis

4
Q

what is angiogenesis and why is it of benefit to cancer growth?

A

creating of new blood vessels which can enable further growth of cancer

5
Q

what is apoptosis?

A

cell death

6
Q

why is cancer a genetic disease?

A

the hallmarks of cancer originate from alterations in genes within the patient themselves rather than being hereditary where the gene alteration would be inherited from the parent

7
Q

what alterations in genes can lead to cancer?

A

apoptosis does not occur
loss of tumor suppressor genes - the cell cycle can run on unchecked while abnormal cells are produced
overactive oncogens promote tumor growth

8
Q

what are oncogens?

A

tumor promoting genes found secondary to mutation

9
Q

what is an example of a tumor suppressor gene and the effect if it is altered?

A

P53 checkpoint gene - halts mitosis if DNA is damaged, if altered cell cycle will not be stopped and altered DNA will continue

10
Q

define neoplasia

A

new growth - abnormal

11
Q

define tumor

A

a swelling (inferred to be neoplasia)

12
Q

define benign

A

neoplasia that forms a solid cohesive tumor and does not metastasise

13
Q

define malignant

A

neoplasm with the capacity for local invasion and metastasis

14
Q

define cancer

A

malignant tumor

15
Q

define metastasis

A

development of secondary tumor remote from the primary tumor

16
Q

what are the 2 features used to describe tumors?

A

tissue of origin

status (benign or malignant)

17
Q

what are the 3 main tissues of origin for tumors?

A

epithelial cell
mesenchymal cell
round cell

18
Q

what is a malignant tumor of epithelial tissue known as?

A

carcinoma

19
Q

what is a malignant tumor of the mesenchymal tissue known as?

A

sarcoma

20
Q

what is malignant cancer of the lymphocytes known as?

A

lymphoma

21
Q

what is malignant cancer of the mast cells known as?

A

mast cell tumor

22
Q

what is the suffix used in benign tumors?

A

—oma

23
Q

what are the important clinical features of a cancer?

A

effect on the host

response to treatment

24
Q

what is the response of a cancer to treatment a reflection of?

A

tumor growth
tumor grade
tumor behaviour

25
Q

what are the main areas of tumor behaviour assessed?

A

local behaviour
metastatic potential
paraneoplastic effects

26
Q

do tumors grow at a steady rate?

A

no - growth kinetics vary with time

27
Q

when does most of the tumor growth occur?

A

before detection

28
Q

what is the effect of tumor growth occurring mostly when undetected?

A

tumor can be quite advanced before it is detected

29
Q

when can a tumor be detected by palpation or radiography?

A

once 1cm in diameter
0.5-1g in weight
made of ~10^9 cells

30
Q

what is the growth fraction of a tumor?

A

the proportion of actively dividing cells within the tumor

31
Q

what is time for tumor to double in size a reflection of?

A

growth fraction of the tumor

32
Q

what happens to tumor doubling time as the tumor grows?

A

tends to lengthen

33
Q

what are tumor growth characteristics described in terms of?

A

tumor doubling time

34
Q

when is the tumor most susceptible to treatment?

A

during the exponential growth phase when the tumor is usually undetectable

35
Q

what happens to the tumors susceptibility to treatment as growth slows and they become detectable?

A

less susceptible to radiation or chemo than healthy gut and bone marrow

36
Q

what does the response of a tumor to chemo and radiotherapy depend on?

A

growth fraction of the tumor as rapidly dividing cells are susceptable

37
Q

once tumors are detectable what has happened to the growth fraction?

A

it is reaching plateu

38
Q

what tumor is the exception when it comes to the relationship between tumor size and growth fraction?

A

lymphoma - remains susceptible to chemo and radiotherapy as still grows rapidly even when tumor burden is high

39
Q

what effect will tumor treatment have on the body once tumor is palpable?

A

proportion of dividing cells in tumor is often less than that in normal, rapidly dividing body tissues such as intestinal epithelium and bone marrow
treatments to tackle rapidly dividing cells are likely to be toxic to the body

40
Q

are tumors formed of homogenous cells?

A

no - mass of heterogenous cells some of which are rapidly dividing and others that are slower

41
Q

do cancer cells remain the same as they grow?

A

no - modify their properties mainly by small, sequential mutations

42
Q

what can be used to predict the likely behaviour of a tumor?

A

a number of cytological and histological features

43
Q

what does the grade of a tumor depend on?

A
mitotic rate (speed of division)
cellular and nuclear characteristics and how different they are from normal
44
Q

what is tumor grading important for?

A

prognosis

45
Q

what does benign and malignant tumor behaviour differ according to?

A
rate of growth
manner of growth
effect on adjacent tissues
surgery
metastasis
effect on host
paraneoplastic effects
46
Q

what is the general behaviour of benign tumors?

A
slow growth
expansive, well defined boundaries
minimal effect on adjacent tissues
surgery is potentially curative
metastasis does not occur
effect on the host is often minimal but can be life-threatening if it bleeds or is in vital organ
paraneoplastic effects are possible
47
Q

what is the general behaviour of malignant tumors?

A

often rapid, perpetual growth
invasive, poorly defined boundaries
invasive, often serious effect on adjacent tissues
surgery only curative if complete resection with 2-3 cm margins and no metastasis
metastasis occurs
effect on the host is often life-threatening
paraneoplastic effects are possible

48
Q

how do malignant tumors grow?

A

by local invasion and may extend microscopically into surrounding tissues which cannot be appreciated by eye (lab analysis essential)

49
Q

what are the physical clues of local tumor invasion?

A

diffuse, indistinct boundaries
fixation of the tumor in one or more planes
thickening of adjacent tissues due to invasion
spontaneous bleeding due to angiogenesis

50
Q

what is a feature of malignancy?

A

the ability to spread to distant tissues

51
Q

how may metastasis occur?

A

via the blood producing secondary tumors in any body organ
via lymphatics, first to local and regional lymph nodes
transcoelomic across the pleural or peritoneal space
iatrogenic during FNA

52
Q

what is the most common site for development of haematogenous secondary tumors?

A

lungs

53
Q

where are primary lung tumors seen?

A

more rarely (seen in cats) but will metastasise to peripheral sites (e.g. digit)

54
Q

what are other common sites of metastasis?

A

those with high blood flow e.g. liver, spleen, kidneys, bone and CNS

55
Q

what is the largest malignant tumor usually?

A

the primary

56
Q

what are paraneoplastic syndromes?

A

signs arising from the indirect effect of tumors production and release of biologically active substances

57
Q

what may be the first indication of neoplastic disease?

A

paraneoplastic syndromes

58
Q

how dangerous can PNS be to the patient?

A

may be life threatening before the cancer directly kills the patient

59
Q

what are the main haematologic PNS seen?

A

anaemia
throbocytopenia
leukopenia

60
Q

what element of PNS causes anaemia?

A

reduction in available iron so fewer RBC

61
Q

what is one of the most common haematologic PNS in dogs and cats?

A

anaemia

62
Q

what are the signs of anaemia?

A

weakness
lethargy
tachypnoea

63
Q

what are the signs of thrombocytopenia?

A

bleeding

64
Q

what are the signs of leukopenia?

A

susceptibility to infection

65
Q

what is hyperviscosity syndrome?

A

increased blood cell numbers leading to sludging blood and poor circulation

66
Q

what can cause hyperviscosity syndrome?

A

leukaemia
primary polycythaemia
secretion of excess erythropoetin by certain tumors casing secondary polycythaemia
excess gamma globulins secreted by certain tumors

67
Q

what provides the effects of hyperviscosity syndrome?

A

excess protein

excess RBC

68
Q

what are the clinical signs of hypervisocity syndrome?

A
lethargy
tremors
thromboembolism
disorientation
episodic weakness
bleeding
ataxia
seizures
retinal haemorrhage and detachment
69
Q

what tumors often cause hyperhistaminaemia?

A

mast cell tumors

70
Q

in what animals are mast cell tumors common?

A

dogs

71
Q

how can hyperhistaminaemia be caused?

A

mast cell tumors releasing histamine and vasoactive amines especially when handled for FNA or surgery

72
Q

what effects can be caused by hyperhistaminaemia?

A

local

systemic

73
Q

what are the local effects of hyperhistaminaemia?

A

oedematous swelling with erythema and pruritus
tendancy for localised bleeding
delayed wound healing or dehiscence

74
Q

what are the systemic effects of hyperhistaminaemia?

A
anaphylactic shock (release of histamine leading to vasodilation and hypotension)
gastroduodenal ulcers
75
Q

how can anaphylactic shock due to hyperhistaminaemia be prevented during mast cell tumor surgery?

A

premedication with antihistamine prior to surgical manipulation

76
Q

how can gastroduodenal ulcer due to hyperhistaminaemia be prevented during mast cell tumor surgery?

A

treat with H2 antagonist or proton pump inhibitor (omeprazole)

77
Q

what are cancer related immune mediated reactions caused by?

A

cross reactivity between cancer cells and healthy cells

78
Q

what are the main immune mediated PNS?

A
IMHA and or thrombocytopenia
immune mediated nephropathy
myasthenia gravis
feline paraneoplastic alopecia
pemphigus foliaceous
79
Q

what can immune mediated neuropathies be caused by?

A

insulinoma

80
Q

what is myasthenia gravis seen secondary to?

A

thymoma

81
Q

when is feline paraneoplastic alopecia, ‘shiny skin disease’, seen?

A

secondary to pancreatic and biliary carcinoma

82
Q

what is pemphigus foliaceous (skin disease) secondary to?

A

thymoma

83
Q

what tumor types can release hormones or hormone-like substances that have PNS effects?

A

non-endocrine as well as endocrine

84
Q

what are the 2 main endocrine related PNS?

A

hypercalcaemia

hypoglycaemia

85
Q

what is the most common endocrine related PNS in dogs?

A

hypercalcaemia

86
Q

is hypercalcaemia as PNS seen often in cats?

A

no

87
Q

how is hypercalcaemia caused as a paraneoplastic syndrome?

A

tumors release a parathormone-like substance called parathyroid hormone related peptide (PTHrp) which increases total and ionised calcium concentrations

88
Q

what cancer is hypercalcaemia as a PNS most commonly seen with?

A

lymphoma

(also anal sac adenocarcinoma, multiple myloma and carcinoma/sarcoma with metastasis

89
Q

what are the clinical signs of hypercalcaemia?

A
PUPD
anorexia
vomiting
lethargy
depression
muscular weakness
bradycardia
90
Q

how does hypercalcaemia lead to PUPD?

A

antagonises ADH and renal damage

91
Q

how does hypocalcaemia lead to anorexia?

A

nausea

92
Q

how does hypocalcaemia lead to vomiting?

A

GI effects

93
Q

how does hypercalcaemia lead to lethargy and depression?

A

neurological depression

94
Q

how does hypercalcaemia lead to muscular weakness?

A

neuromuscular depression

95
Q

how does hypercalcaemia lead to bradycardia?

A

cardiovascular effects

96
Q

what effects of hypercalcaemia are the most importance?

A

renal

97
Q

what do the renal effects of hypercalcaemia cause?

A

dehydration which is worsened by vomiting

renal failure

98
Q

how is hypoglycaemia caused as a PNS?

A

pancreatic insulinoma produces insulin
tumors that excessively consume glucose
release of insulin like factor which has the same effect as insulin and causes hypoglycaemia

99
Q

what tumors lead to excessive consumption of glucose?

A

hepatoma
hepatocellular carcinoma
large intra-abdominal mass
chronic lymphocytic leukaemia

100
Q

what are the main tumors which produce insulin like factor?

A

leiomyoma
GI stromal tumor
(arise from smooth muscle)

101
Q

what is cancer cachexia?

A

weight loss
muscle loss
fat loss

102
Q

what is cancer cachexia caused by?

A

abnormal metabolism leading to enhanced catabolism
lots of energy used
reduced food intake due to inappetance

103
Q

how is fever seen as a PNS?

A

pyrogens cytokines (e.g. IL-1 and IL-6) are produced by the tumor

104
Q

what is critical in cancer management?

A

evaluation of type or spread of tumor

105
Q

what must be done before any cancer treatment is given?

A

accurate diagnosis of tumor type and grade

106
Q

what are the aims of cancer investigations?

A

make a histological / cytological analysis of type and grade
determine the extent of the disease (stage)
investigate and treat any tumor related or concurrent complications

107
Q

what is the investigation and treatment of tumor related and concurrent complications an assessment of?

A

the patients ability to tolerate therapy

overall prognosis

108
Q

what is involved in obtaining a diagnosis?

A
history
physical exam
lab tests (biochem and haem)
imaging of suspected area
biopsy
109
Q

when can an accurate diagnosis of caner only be made?

A

microscopic examination of representative tissues or cells

110
Q

what should be done with all excised masse?

A

submitted for histology
or
fixed and stored in case the owners change their mind or the patient deteriorates

111
Q

what does cytology analyse?

A

the cells

112
Q

what are the possible methods of gaining samples for cytology?

A

touch / impression preparations
FNA
analysis of body fluids / effusions

113
Q

is prep needed for an FNA?

A

no

114
Q

what tube is used to store body fluid or effusions?

A

EDTA

115
Q

what indications about the tumor can be made by cytology?

A

nature of tumor

cytological features

116
Q

what are the disadvantages to assessing a tumor with cytology?

A

may not provide a definitive diagnosis
false negatives may occur
difficult to differentiate inflammation from neoplasia

117
Q

when is it especially difficult to differentiate tumor from neoplasia?

A

if tumor outgrows blood supply or is necrotic

118
Q

how can histological examination of the tumor be made?

A

surgical
needle (Tru-Cut)
punch biopsy

119
Q

what is the most accurate method of tumor diagnosis?

A

large biopsy sample

120
Q

what does a large biopsy sample for histology show?

A

cellular features of malignancy
tumor architecture
invasion of adjacent tissues
evidence of metastatic behaviour

121
Q

what demonstrates evidence of metastatic behaviour?

A

presence in blood vessels and/or lymphatics

122
Q

what are the 2 surgical biopsy techniques?

A

incisional

excisional

123
Q

what is an incisional biopsy?

A

part of the tumor taken along with some healthy tissue

124
Q

what is an excisional biopsy?

A

full tumor taken with large margins

125
Q

what are the key features of a good biopsy?

A

representative sample
avoiding superficial ulceration, inflammation and necrosis
adequate depth
boundary between tumor and normal tissue included

126
Q

is a biopsy always performed?

A

not if the risk of obtaining the biopsy is too great (e.g. brain tumor) or if performing the biopsy will not alter the treatment that is prescribed (e.g. splenectomy for any type of mass)

127
Q

what is the role of tumor staging?

A

the feasibility of therapy and prognosis

128
Q

what is identified through clinical staging?

A

cytological or histological grade
local invasion
metastatic spread

129
Q

what is the most common tumor staging system?

A

WHO TNM system

130
Q

what does TNM stand for?

A

tumor
nodes
metastasis

131
Q

what does TNM assess?

A

tumor - size and invasiveness
nodes - assessment of local draining lymph nodes for evidence of spread
metastasis - spread to other organs

132
Q

what is T0 in the TNM system?

A

no evidence of primary tumor

133
Q

what is T1-T4 in the TNM system?

A

size and/or extent of the primary tumor

134
Q

what is N0 in the TNM system?

A

no regional lymph node involvement

135
Q

what is N1-N4 in the TNM system?

A

involvement of regional lymph nodes, number of lymph nodes and/or extent of spread

136
Q

what is M0 in the TNM system?

A

no distant metastasis

137
Q

what is M1, M2 in the TNM system?

A

distant metastasis is present, single or multiple

138
Q

how is metastatic disease assessed?

A

history
physical exam
thoracic radiographs (3 views) or CT
abdominal radiographs and ultrasounds
FNA of appropriate area depending on cancer type
bone marrow aspirate (if haematological abnormailities)

139
Q

how is lymph node metastasis assessed?

A

using knowledge of principle routes of lymphatic drainage relevant local and regional lymph nodes are evelautaed

140
Q

how are lymph nodes evaluated to assess for lymph node metastasis?

A

palpation of LN size and texture
imaging of deeper LN
FNA to distinguish tumor spread from reactive hyperplasia due to tumor

141
Q

what lymph nodes should be palpated to assess for local invasion?

A

first lymph node that will be affected (e.g. popliteal if on the hind digit)

142
Q

what should be considered when deciding on cancer treatment?

A

staging
tumor grade
known tumor behaviour

143
Q

why is staging not exact?

A

there are microscopic tumor extensions or deposits that are impossible to detect in vivo

144
Q

when may staging not be used?

A

if it will not affect the treatment

consider cost

145
Q

what is the decision to treat cancer made based on?

A
nature of disease
treatment options
potential side effects
prognosis with and without treatment
cost
146
Q

what will be considered when tailoring treatment to the individual case?

A

tumor biology
histology
grade
stage

147
Q

what is the ideal aim of cancer treatment?

A

cure

148
Q

what is involved in cancer cure?

A

all cells that have the capacity for tumor regeneration are eradicated

149
Q

what is the more achievable treatment aim?

A

remission

150
Q

what is remission?

A

all clinical evidence of cancer has disappeared

occult cancer cells remain and relapse will occur at some point

151
Q

what is the aim of palliative cancer treatment

A

reduce pain / improve sense of well being and / or correct physiological malfunction

152
Q

what is usually chosen when deciding on cancer treatment for pets?

A

best quality of life as opposed to greatest number of cures

153
Q

what is the only method of treatment likely to affect a cure for cancer?

A

complete surgical excision

154
Q

what are the 3 main methods of cancer treatment in animals?

A

surgical excision
radiation
chemotherapy with anti cancer / cytotoxic drugs

155
Q

how are most cancer treatment modalities used except for systemic cancers?

A

modalities combined

156
Q

how can cancer treatment modalities be combined to treat cancer?

A

chemo and/or radiation after surgical debulking
chemo and/or radiation after surgery to control metastasis
chemo and/or radiation to reduce tumor size before surgery

157
Q

what is the most effective treatment for the majority of solid tumors?

A

surgery

158
Q

what is local excision “lumpectomy” suitable for?

A

truly benign tumor (fibroma, lipoma, benign mammary tumor)

159
Q

what is involved in a wide local excision of a tumor?

A

wider margins (1-2cm) and two tissue planes of apparently normal tissue excised to ensure all tumor is removed so that regrowth doesn’t occur

160
Q

what is wide local excision suitable for?

A

basal cell carcinoma
squamous cell carcinoma
mast cell tumor

161
Q

when is wide local excision more challenging?

A

if there is insufficient normal tissue to be able to close the wound (e.g. mass on chest wall / limbs)
often requires local excision of underlying bone

162
Q

what tumors infiltrate adjacent tissues more widely than 1-2cm margins?

A

soft tissue sacromas

163
Q

what does resection of tumors infiltrating more than 1-2cm of local tissues involve?

A

removing every tissue compartment which the tumor involves

164
Q

what is the resection involving removing every tissue compartment which the tumor involves called?

A

en bloc or compartmental resection

165
Q

what is often needed to close the wound after en bloc resection?

A

reconstructive procedures

166
Q

when does failure of surgical tumor excision occur?

A

regrows at the primary site due to incomplete resection
metastasis has already occurred
tumor is systemic

167
Q

what is regrowth of a tumor at the primary site due to?

A

site involving vital structures that cannot be removed

infiltration of tumor due to inadequate margins

168
Q

what is surgical debulking?

A

removal of as much of a surgically incurable malignant tumor as possible

169
Q

what is surgical debulking followed by?

A

subsequent therapy (e.g. drugs, radiation)

170
Q

what are the general rules of surgical tumor resection?

A

margin of normal tissue used
mark out clear margins
cut large and deep to reduce regrowth risk
use 2 sets of instruments (excision and closure)

171
Q

what is the purpose of 2 sets of instruments for excision and closure in cancer surgery?

A

prevent iatrogenic tumor seeding

172
Q

how should the form for biopsy samples to an external lab be filled in?

A

provide history
mark particular margin with ink if there are concerns
identify and orientate samples with labels
submit all samples and entire tumor

173
Q

what are the general considerations for post op management of cancer patients?

A

nutrition
analgesia
wound care/management
rehab needed to regain functionality

174
Q

what is the effect of excessive tension on a wound?

A
compromise of circulation
slow wound healing
wound breakdown
necrosis
distortion of anatomic areas
175
Q

what does tension over an artery lead to?

A

ischaemia

176
Q

what does tension of a wound over veins and lymphatics do?

A

lead to oedema

177
Q

what are the 2 main factors in wound breakdown?

A

patient factors

wound factors

178
Q

what are the patient factors which affect wound healing?

A

intrinsic - concurrent disease, nutrition

extrinsic - chemo, steroids, radiotherapy

179
Q

what are the wound factors that can lead to wound breakdown?

A
neoplasia
tissue handling/haemostasis
tension
motion
sutures 
infection 
patient interferance
180
Q

what should happen if wound breakdown occurs?

A

manage wound
do not resuture
allow to heal via second intention

181
Q

what is a surgical wound that breaks down classed as?

A

dirty wound

182
Q

how should wounds that suffer wound breakdown be allowed to heal?

A

via second intetion

183
Q

what is seroma?

A

accumulation of fluid at the level of a wound

184
Q

how can seroma formation be prevented?

A

reduce dead space
place drains
rest

185
Q

how should seroma be treated?

A

can leave to recover alone
pressure bandage placed
provide further drainage

186
Q

how should wound infection be treated?

A

drainage
allow to heal via second intention
antibiotics based on culture and sensitivity
exploration of wound if necessary

187
Q

what is radiation oncology?

A

the medical use of ionising radiation as an integral part of cancer treatment by killing or controlling malignant cells

188
Q

what is radiation most effective for?

A

local treatment following incomplete surgical excision of tumor

189
Q

how does radiation work?

A

ionisation - removal of an orbiting electron from the shell of an atom

190
Q

what are the 2 main methods for application of radiation to patients?

A

brachytherapy

external beam radiation therapy or teletherapy

191
Q

what is the most common form of radiation therapy used in veterinary practice?

A

external beam radiation therapy or teletherapy

192
Q

what are the 2 types of radiation used in radiation therapy?

A

electrons (beta particles) - easily shielded

high energy x-rays (harmful)

193
Q

how does brachytherapy work?

A

radioactive substance emits gamma rays or beta particles close to tumor

194
Q

how is brachytherapy administered?

A

applied to tumor surface
implanted within tumor (seeds)
administered systemically but concentrated on tumor

195
Q

how does external beam radiation therapy or teletherapy work?

A

radiation therapy given by an external radiation source at a distance from the body

196
Q

what is the most commonly used method of external beam radiation therapy or teletherapy?

A

LINAC - linear accelerator

197
Q

how is external beam radiation therapy or teletherapy dosed?

A

multiple fractions (doses) given over 4-6 weeks

198
Q

why is external beam radiation therapy or teletherapy limited?

A

restricted availability of fixed radiation source or LINAC

199
Q

what are the acute side effects to radiation therapy?

A
erythema
vesiculation
desquamation
severe exfoliative dermatitis
localised hair loss
200
Q

what are the late toxicity side effects of radiation therapy?

A

depigmentation
dermal fibrosis
osteonecrosis
neural necrosis

201
Q

what is chemotherapy?

A

the use of chemicals to destroy infective agents

202
Q

why are risk assessments for chemotherapy necessary?

A

drugs are highly toxic and potentially dangerous to vet, support staff and owners

203
Q

what does tumor response to chemotherapy depend on?

A

growth fraction

204
Q

what cells are most susceptible to chemotherapy?

A

rapidly dividing

205
Q

when are tumors more sensitive to chemotherapy?

A

early stages of development where they are rapidly growing and dividing

206
Q

when are tumors less susceptible to chemo or radiation?

A

when they are detectable and growing more slowly

207
Q

what are chemotherapy drugs most effective against?

A

rapidly growing or dividing cells

208
Q

what are the rapidly dividing cells found in the body during chemo?

A

cancer cells
bone marrow
GI tract

209
Q

what do chemotherapy drugs act upon?

A

processes in cell growth and division (e.g. DNA replication and metabolic activities)

210
Q

what does response to chemotherapy depend on?

A

tumor growth rate

drug resistance

211
Q

how should a chemo dose be chosen?

A

highest possible dose to affect maximum fractional kill with minimum side effects
i.e. the dose with maximum acceptable side effects

212
Q

when is chemotherapy ideally used?

A

when tumor burden is at it’s lowest and growth fraction highest

213
Q

when is tumor burden likely to be at it’s lowest and growth fraction highest?

A

early on or after surgical debulking

214
Q

what regime is used to give chemotherapy?

A

repeated doses of a range of drugs allowing recovery time

typically 3 week cycles

215
Q

how is chemotherapy dosing calculated?

A

function of surface area in metres squared

216
Q

what neoplasia is typically highly sensitive to chemo?

A

lymphoma
myeloma
some forms of leukaemia

217
Q

what neoplasia typically has moderate sensitivity to chemo?

A

high grade sarcomas

mast cell tumors

218
Q

what neoplasia is typically poorly sensitive to chemotherapy?

A

most slow growing sarcomas
most carcinomas
melanomas

219
Q

what is the favoured approach in chemotherapy?

A

combination therapy

220
Q

what is combination therapy?

A

combine different classes of chemotherapy agents with different mechanisms of action and different side effects?

221
Q

what is the benefit of combination chemotherapy?

A
combinations are more effective than a single agent
greater tumor kill is achieved
less resistance
fewer side effects
may be better tolerated
222
Q

what are chemotherapy protocols often named after?

A

the agents used

223
Q

what is the common feline chemo regime for lymphoma?

A

C (cyclophosphomide)
O (Oncovin)
P (prednisolone)

224
Q

what is the common canine chemo regime for lymphoma?

A

C (cyclophosphomide)
H (hydroxydaunorubicin - doxorubicin)
O (Oncovin)
P (prednisolone)

225
Q

what is chemotherapy used as a first line treatment for?

A

diseases that are systemic in nature (surgery non-curative or possible)

226
Q

why do systemic cancers normally respond well to chemotherapy?

A

high growth fraction

227
Q

what cancers is first-line chemotherapy used to treat?

A

lymphoma
some forms of leukaemia
multiple myloma

228
Q

what is adjunctive chemotherapy used for?

A

solid tumors where chemo would not be of value as the sole therapy

229
Q

what cancers are often treated with adjunctive chemotherapy?

A

carcinoma

sarcoma

230
Q

what is the main aim of chemotherapy as an adjunct to surgical and/or radio therapy?

A

reduction of tumor mass to enable surgical resection

try to prevent / delay metasiasis

231
Q

what is metronomic chemotherapy?

A

palliative low doses of chemotherapy drugs

232
Q

how often is metronomic chemotherapy given?

A

daily

233
Q

what is the target of metronomic chemotherapy?

A

endothelium or tumor stroma

234
Q

what is the effect of targeting tumor stroma in metronomic chemotherapy?

A

anti-angiogenic to slow tumor growth

235
Q

what is the aim of metronomic chemotherapy?

A

minimise toxicity and palliation

slows disease progression

236
Q

what is chemoembolisation?

A

local, directed delivery of chemotherapy drug and embolization to treat inoperable solid tumors

237
Q

where is chemo applied during chemoembolisation?

A

injected into blood vessel that supplies the tumor via fluroscopy

238
Q

how is chemoembolisation performed?

A

chemo drug is injected into the blood vessel supplying the tumor under fluroscopy
synthetic (embolic) material is placed inside the blood vessel to trap the chemotherapy within the tumor

239
Q

what is involved in the safe use of chemotherapy?

A

local rules and guidelines in place for handling cytotoxic drugs
all employees should be aware of the use of cytotoxic drugs
use PPE
sealed or closed system for administration
cleaning procedures
use of chemo room
clear disposal protocol
pregnant women should not handle chemo drugs

240
Q

what are the safety precautions that should be taken when handling cytotoxic drugs?

A

chemo room locked
use cabinet with vertical flow containment hood
use plastic pad to ensure drug is never in direct contact with surface
use Luer-Lock syringes for administration
materials used gathered into sealed plastic bag and disposed of in chemo waste

241
Q

what is involved in the nursing care of patients receiving chemotherapy with regards to management of cytotoxic waste?

A

designated kennel with clear ID of agents used
PPE worn while caring for patient
all materials that are in contact with the animal should be regarded as potentially contaminated
use cytotoxic waste bin

242
Q

what is the risk period following chemo drug administration?

A

time when cytotoxic material may be found in patients waste - varies between drugs

243
Q

how should chemotherapy patients be managed at home to ensure that owners are kept safe?

A

keep children and other pets away from patients
wash bowls and toys separately from other items
wash bedding separately from other laundry using detergent and bleach if soiled
use gloves when cleaning up and dispose of into double bag
handwashing is key
after cleaning an area disinfect with household bleach

244
Q

what should be done after washing chemo patients laundry?

A

machine should be put on an empty washing cycle before any other laundry is washed

245
Q

how should urine, faeces and vomit from a chemo patient be cleaned up?

A

solid/semi solid waste and small amounts of absorbent material may be flushed down the toilet
larger amounts of waste should be disposed of in regular rubbish - double bagged

246
Q

what are chemo dosages chosen usually a compromise between?

A

efficacy and safety

247
Q

what are the inherent toxicities of all chemotherapy agents due to?

A

effect on dividing cells

248
Q

what healthy cells are most affected by chemotherapy?

A

normal tissues with high cell turnover (e.g. bone marrow and GI tract) which will recover faster than tumor

249
Q

what causes the direct GI toxicity of chemotherapy?

A

death and loss of intestinal epithelial cells

250
Q

when does GI toxicity due to chemo usually occur?

A

5-10 days after drug administration

251
Q

what are the main signs of GI toxicity due to chemo?

A

stomatitis
vomiting
mucoid or haemorrhagic diarrhoea

252
Q

what can cause early nausea and vomiting in chemo patients?

A

drugs may induce early nausea and vomiting by stimulation of CRTZ (chemoreceptor trigger zone)

253
Q

how is GI toxicity due to chemo treated?

A

symptomatic
IVFT
anti-emetics
gastro-protectants for any gastric ulceration
parenteral antibiotics if haemorrhagic diarrhoea or immunosuppressed

254
Q

what coat changes are seen in chemo patients?

A

cats usually only loose whiskers

not a problem in most dogs

255
Q

does coat loss occur in dogs due to chemotherapy?

A

some breeds are susceptible to significant hair loss leading to a patchy coat

256
Q

what may happen to the coat of an old English sheepdog following chemotherapy?

A

coat may regrow in a different colour

257
Q

what is myelosuppression?

A

damage and suppression of bone marrow

258
Q

what must be performed before any chemotherapy?

A

haematology to check WBC

259
Q

when may chemo be delayed or reduced following haematology?

A

if there is mylosuppression

260
Q

what does myelosuppression cause?

A

neutropenia (life threatening)
thrombocytopenia
anaemia

261
Q

what is the patient at risk of if the neutrophil count is <2 x 10^9 per L?

A

sepsis from translocation of enteric bacteria

262
Q

what does management of neutropenia depend on?

A

absolute cell count

clinical signs

263
Q

why does translocation of enteric bacteria occur?

A

enterocytes damaged by chemo
gut becomes more leaky
low neutrophils reduces ability to fight infection

264
Q

what is the recommended action if there is no neutropenia (>3)?

A

continue chemo

repeat WBC before next chemo dose

265
Q

what is the recommended action if there is mild neutropenia (2-3)?

A

reduce dosage by 50%

repeat WBC count 10-14 days post treatment admin

266
Q

what is the recommended action if there is moderate neutropenia (<2)?

A

stop chemo
monitor patient and WBC
avoid hospitalisation
administer antibiotics if patient is predisposed to infection

267
Q

why should moderately neutropenic patients not be hospitalised?

A

infection risk is higher in hospital

268
Q

what is the recommended action if there is severe neutropenia (<1) but patient is asymptomatic / afebrile?

A

stop all cytotoxic treatment
antibiotics
collect samples for culture

269
Q

what is the recommended action if there is severe neutropenia (<1) and the patient is sick / pyrexic?

A

stop all cytotoxic treatment
hospitalised
IV fluids given
bacteriocidal antibiotics

270
Q

what is neutropenia an indication of?

A

maximum tolerated dose being reached / approched

271
Q

what may myelosuppression be associated with?

A

better prognosis as maximum tolerated dose is being used

272
Q

when is hypersensitivity / anaphylaxis to chemo seen?

A

rare but reported in dogs with doxyrubicin

273
Q

what should you do if hypersensitivity or anaphylaxis reaction to chemo occurs?

A

IVFT
soluble corticosteroids
adrenaline
antihistamines

274
Q

when may phlebitis or tissue necrosis occur?

A

if topical or extravasate (outside vein)

275
Q

what are the 2 main types of chemo drugs that can cause phlebitis or tissue necrosis?

A

irritants

vesicants

276
Q

what can irritant chemo drugs cause?

A

local inflammatory reactions at infusion site e.g. swelling, pain

277
Q

what can vesicant chemo drugs cause?

A

severe and/or irreversible tissue injury and necrosis

278
Q

what are 2 common vesicant chemo drugs?

A

Vincristine

Doxorubicin

279
Q

what can be done to reduce the risk of extravasation?

A

drugs in sealed system
adequate patient restraint
clean stick IV catheter used for administration
catheter flushed before and after

280
Q

how is perivascular leakage of doxorubicin treated?

A
stop infusion but don't remove catheter
aspirate extravasated drug through catheter and give intralesional saline to dilute drug
draw back blood and remove catheter
IV hydrocortisone
cold compress
281
Q

what is used for Vincristine extravasation?

A

warm compress

DMSO

282
Q

what is the antidote for extravasated doxorubicin?

A

dexrazoxane

283
Q

what are some specific drug toxicities?

A

sterile haemorrhagic cystitis
cardiotoxicity
hepatotoxicity
nephrotoxicity

284
Q

what causes sterile haemorrhagic cystitis?

A

metabolites of cyclophosphomide in the urine which have an irritant effect on the bladder leading to cystitis

285
Q

what drug is associated with sterile haemorrhagic cystitis?

A

cyclophosphomide

286
Q

what are the signs of sterile haemorrhagic cystitis?

A

profuse haematuria

287
Q

how can sterile haemorrhagic cystitis be treated?

A

no specific treatment
sometimes irreversible
MESNA may be protective

288
Q

how can risk of sterile haemorrhagic cystitis be minimised?

A

administer drug in early morning so it is not retained in the bladder overnight
ensure good fluid intake
encourage frequent urination
concurrent steroids or furosemide will assist diuresis
monitor urine for blood / protein via dipstick before and after each chemo treatment

289
Q

what chemo drug causes cardiotoxicity?

A

doxorubicin

290
Q

what can acute cardiotoxicity from doxorubicin lead to ?

A

tachyarrhythmias

291
Q

how can acute cardiotoxicity due to doxorubicin be prevented?

A

slow infusion over at least 15 mins

monitor pulse

292
Q

wha

A
293
Q

how is chronic cardiotoxicity from doxorubicin prevented?

A

don’t give more than the cumulative dose of 240 mg/metres squared over 8 doses

294
Q

what chemo drug causes hepatotoxicity?

A

lomustine (CCNU)

295
Q

what is the sign of hepatotoxicity due to lomustine?

A

increase in liver enzymes

296
Q

when should lomustine treatment be delayed or discontinued?

A

if liver enzymes are 3x upper reference range

297
Q

how can hepatotoxicity due to lomustine be prevented?

A

coadministration with SAMe

monitor biochemistry before each treatment

298
Q

how is nephrotoxicity caused in chemo patients?

A

platinum compounds cause necrosis of proximal tubular cells

299
Q

how can nephrotoxicity in chemo be prevented?

A

administer drugs slowly with IVFT diuresis

monitor urea/creatinine

Decks in X Clinical Veterinary Nursing Theory Class (70):