Oncology Flashcards
what is cancer?
diverse range of conditions with a common theme of persistent, pointless proliferation of host cells often to the detriment of the host
what is the spectrum of behaviour that can be displayed by tumors?
truly benign
highly malignant
local characteristics of malignancy but do not metastasise
what are the 6 features necessary for the development of cancer?
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
what is angiogenesis and why is it of benefit to cancer growth?
creating of new blood vessels which can enable further growth of cancer
what is apoptosis?
cell death
why is cancer a genetic disease?
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
what alterations in genes can lead to cancer?
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
what are oncogens?
tumor promoting genes found secondary to mutation
what is an example of a tumor suppressor gene and the effect if it is altered?
P53 checkpoint gene - halts mitosis if DNA is damaged, if altered cell cycle will not be stopped and altered DNA will continue
define neoplasia
new growth - abnormal
define tumor
a swelling (inferred to be neoplasia)
define benign
neoplasia that forms a solid cohesive tumor and does not metastasise
define malignant
neoplasm with the capacity for local invasion and metastasis
define cancer
malignant tumor
define metastasis
development of secondary tumor remote from the primary tumor
what are the 2 features used to describe tumors?
tissue of origin
status (benign or malignant)
what are the 3 main tissues of origin for tumors?
epithelial cell
mesenchymal cell
round cell
what is a malignant tumor of epithelial tissue known as?
carcinoma
what is a malignant tumor of the mesenchymal tissue known as?
sarcoma
what is malignant cancer of the lymphocytes known as?
lymphoma
what is malignant cancer of the mast cells known as?
mast cell tumor
what is the suffix used in benign tumors?
—oma
what are the important clinical features of a cancer?
effect on the host
response to treatment
what is the response of a cancer to treatment a reflection of?
tumor growth
tumor grade
tumor behaviour
what are the main areas of tumor behaviour assessed?
local behaviour
metastatic potential
paraneoplastic effects
do tumors grow at a steady rate?
no - growth kinetics vary with time
when does most of the tumor growth occur?
before detection
what is the effect of tumor growth occurring mostly when undetected?
tumor can be quite advanced before it is detected
when can a tumor be detected by palpation or radiography?
once 1cm in diameter
0.5-1g in weight
made of ~10^9 cells
what is the growth fraction of a tumor?
the proportion of actively dividing cells within the tumor
what is time for tumor to double in size a reflection of?
growth fraction of the tumor
what happens to tumor doubling time as the tumor grows?
tends to lengthen
what are tumor growth characteristics described in terms of?
tumor doubling time
when is the tumor most susceptible to treatment?
during the exponential growth phase when the tumor is usually undetectable
what happens to the tumors susceptibility to treatment as growth slows and they become detectable?
less susceptible to radiation or chemo than healthy gut and bone marrow
what does the response of a tumor to chemo and radiotherapy depend on?
growth fraction of the tumor as rapidly dividing cells are susceptable
once tumors are detectable what has happened to the growth fraction?
it is reaching plateu
what tumor is the exception when it comes to the relationship between tumor size and growth fraction?
lymphoma - remains susceptible to chemo and radiotherapy as still grows rapidly even when tumor burden is high
what effect will tumor treatment have on the body once tumor is palpable?
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
are tumors formed of homogenous cells?
no - mass of heterogenous cells some of which are rapidly dividing and others that are slower
do cancer cells remain the same as they grow?
no - modify their properties mainly by small, sequential mutations
what can be used to predict the likely behaviour of a tumor?
a number of cytological and histological features
what does the grade of a tumor depend on?
mitotic rate (speed of division) cellular and nuclear characteristics and how different they are from normal
what is tumor grading important for?
prognosis
what does benign and malignant tumor behaviour differ according to?
rate of growth manner of growth effect on adjacent tissues surgery metastasis effect on host paraneoplastic effects
what is the general behaviour of benign tumors?
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
what is the general behaviour of malignant tumors?
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
how do malignant tumors grow?
by local invasion and may extend microscopically into surrounding tissues which cannot be appreciated by eye (lab analysis essential)
what are the physical clues of local tumor invasion?
diffuse, indistinct boundaries
fixation of the tumor in one or more planes
thickening of adjacent tissues due to invasion
spontaneous bleeding due to angiogenesis
what is a feature of malignancy?
the ability to spread to distant tissues
how may metastasis occur?
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
what is the most common site for development of haematogenous secondary tumors?
lungs
where are primary lung tumors seen?
more rarely (seen in cats) but will metastasise to peripheral sites (e.g. digit)
what are other common sites of metastasis?
those with high blood flow e.g. liver, spleen, kidneys, bone and CNS
what is the largest malignant tumor usually?
the primary
what are paraneoplastic syndromes?
signs arising from the indirect effect of tumors production and release of biologically active substances
what may be the first indication of neoplastic disease?
paraneoplastic syndromes
how dangerous can PNS be to the patient?
may be life threatening before the cancer directly kills the patient
what are the main haematologic PNS seen?
anaemia
throbocytopenia
leukopenia
what element of PNS causes anaemia?
reduction in available iron so fewer RBC
what is one of the most common haematologic PNS in dogs and cats?
anaemia
what are the signs of anaemia?
weakness
lethargy
tachypnoea
what are the signs of thrombocytopenia?
bleeding
what are the signs of leukopenia?
susceptibility to infection
what is hyperviscosity syndrome?
increased blood cell numbers leading to sludging blood and poor circulation
what can cause hyperviscosity syndrome?
leukaemia
primary polycythaemia
secretion of excess erythropoetin by certain tumors casing secondary polycythaemia
excess gamma globulins secreted by certain tumors
what provides the effects of hyperviscosity syndrome?
excess protein
excess RBC
what are the clinical signs of hypervisocity syndrome?
lethargy tremors thromboembolism disorientation episodic weakness bleeding ataxia seizures retinal haemorrhage and detachment
what tumors often cause hyperhistaminaemia?
mast cell tumors
in what animals are mast cell tumors common?
dogs
how can hyperhistaminaemia be caused?
mast cell tumors releasing histamine and vasoactive amines especially when handled for FNA or surgery
what effects can be caused by hyperhistaminaemia?
local
systemic
what are the local effects of hyperhistaminaemia?
oedematous swelling with erythema and pruritus
tendancy for localised bleeding
delayed wound healing or dehiscence
what are the systemic effects of hyperhistaminaemia?
anaphylactic shock (release of histamine leading to vasodilation and hypotension) gastroduodenal ulcers
how can anaphylactic shock due to hyperhistaminaemia be prevented during mast cell tumor surgery?
premedication with antihistamine prior to surgical manipulation
how can gastroduodenal ulcer due to hyperhistaminaemia be prevented during mast cell tumor surgery?
treat with H2 antagonist or proton pump inhibitor (omeprazole)
what are cancer related immune mediated reactions caused by?
cross reactivity between cancer cells and healthy cells
what are the main immune mediated PNS?
IMHA and or thrombocytopenia immune mediated nephropathy myasthenia gravis feline paraneoplastic alopecia pemphigus foliaceous
what can immune mediated neuropathies be caused by?
insulinoma
what is myasthenia gravis seen secondary to?
thymoma
when is feline paraneoplastic alopecia, ‘shiny skin disease’, seen?
secondary to pancreatic and biliary carcinoma
what is pemphigus foliaceous (skin disease) secondary to?
thymoma
what tumor types can release hormones or hormone-like substances that have PNS effects?
non-endocrine as well as endocrine
what are the 2 main endocrine related PNS?
hypercalcaemia
hypoglycaemia
what is the most common endocrine related PNS in dogs?
hypercalcaemia
is hypercalcaemia as PNS seen often in cats?
no
how is hypercalcaemia caused as a paraneoplastic syndrome?
tumors release a parathormone-like substance called parathyroid hormone related peptide (PTHrp) which increases total and ionised calcium concentrations
what cancer is hypercalcaemia as a PNS most commonly seen with?
lymphoma
(also anal sac adenocarcinoma, multiple myloma and carcinoma/sarcoma with metastasis
what are the clinical signs of hypercalcaemia?
PUPD anorexia vomiting lethargy depression muscular weakness bradycardia
how does hypercalcaemia lead to PUPD?
antagonises ADH and renal damage
how does hypocalcaemia lead to anorexia?
nausea
how does hypocalcaemia lead to vomiting?
GI effects
how does hypercalcaemia lead to lethargy and depression?
neurological depression
how does hypercalcaemia lead to muscular weakness?
neuromuscular depression
how does hypercalcaemia lead to bradycardia?
cardiovascular effects
what effects of hypercalcaemia are the most importance?
renal
what do the renal effects of hypercalcaemia cause?
dehydration which is worsened by vomiting
renal failure
how is hypoglycaemia caused as a PNS?
pancreatic insulinoma produces insulin
tumors that excessively consume glucose
release of insulin like factor which has the same effect as insulin and causes hypoglycaemia
what tumors lead to excessive consumption of glucose?
hepatoma
hepatocellular carcinoma
large intra-abdominal mass
chronic lymphocytic leukaemia
what are the main tumors which produce insulin like factor?
leiomyoma
GI stromal tumor
(arise from smooth muscle)
what is cancer cachexia?
weight loss
muscle loss
fat loss
what is cancer cachexia caused by?
abnormal metabolism leading to enhanced catabolism
lots of energy used
reduced food intake due to inappetance
how is fever seen as a PNS?
pyrogens cytokines (e.g. IL-1 and IL-6) are produced by the tumor
what is critical in cancer management?
evaluation of type or spread of tumor
what must be done before any cancer treatment is given?
accurate diagnosis of tumor type and grade
what are the aims of cancer investigations?
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
what is the investigation and treatment of tumor related and concurrent complications an assessment of?
the patients ability to tolerate therapy
overall prognosis
what is involved in obtaining a diagnosis?
history physical exam lab tests (biochem and haem) imaging of suspected area biopsy
when can an accurate diagnosis of caner only be made?
microscopic examination of representative tissues or cells
what should be done with all excised masse?
submitted for histology
or
fixed and stored in case the owners change their mind or the patient deteriorates
what does cytology analyse?
the cells
what are the possible methods of gaining samples for cytology?
touch / impression preparations
FNA
analysis of body fluids / effusions
is prep needed for an FNA?
no
what tube is used to store body fluid or effusions?
EDTA
what indications about the tumor can be made by cytology?
nature of tumor
cytological features
what are the disadvantages to assessing a tumor with cytology?
may not provide a definitive diagnosis
false negatives may occur
difficult to differentiate inflammation from neoplasia
when is it especially difficult to differentiate tumor from neoplasia?
if tumor outgrows blood supply or is necrotic
how can histological examination of the tumor be made?
surgical
needle (Tru-Cut)
punch biopsy
what is the most accurate method of tumor diagnosis?
large biopsy sample
what does a large biopsy sample for histology show?
cellular features of malignancy
tumor architecture
invasion of adjacent tissues
evidence of metastatic behaviour
what demonstrates evidence of metastatic behaviour?
presence in blood vessels and/or lymphatics
what are the 2 surgical biopsy techniques?
incisional
excisional
what is an incisional biopsy?
part of the tumor taken along with some healthy tissue
what is an excisional biopsy?
full tumor taken with large margins
what are the key features of a good biopsy?
representative sample
avoiding superficial ulceration, inflammation and necrosis
adequate depth
boundary between tumor and normal tissue included
is a biopsy always performed?
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)
what is the role of tumor staging?
the feasibility of therapy and prognosis
what is identified through clinical staging?
cytological or histological grade
local invasion
metastatic spread
what is the most common tumor staging system?
WHO TNM system
what does TNM stand for?
tumor
nodes
metastasis
what does TNM assess?
tumor - size and invasiveness
nodes - assessment of local draining lymph nodes for evidence of spread
metastasis - spread to other organs
what is T0 in the TNM system?
no evidence of primary tumor
what is T1-T4 in the TNM system?
size and/or extent of the primary tumor
what is N0 in the TNM system?
no regional lymph node involvement
what is N1-N4 in the TNM system?
involvement of regional lymph nodes, number of lymph nodes and/or extent of spread
what is M0 in the TNM system?
no distant metastasis
what is M1, M2 in the TNM system?
distant metastasis is present, single or multiple
how is metastatic disease assessed?
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)
how is lymph node metastasis assessed?
using knowledge of principle routes of lymphatic drainage relevant local and regional lymph nodes are evelautaed
how are lymph nodes evaluated to assess for lymph node metastasis?
palpation of LN size and texture
imaging of deeper LN
FNA to distinguish tumor spread from reactive hyperplasia due to tumor
what lymph nodes should be palpated to assess for local invasion?
first lymph node that will be affected (e.g. popliteal if on the hind digit)
what should be considered when deciding on cancer treatment?
staging
tumor grade
known tumor behaviour
why is staging not exact?
there are microscopic tumor extensions or deposits that are impossible to detect in vivo
when may staging not be used?
if it will not affect the treatment
consider cost
what is the decision to treat cancer made based on?
nature of disease treatment options potential side effects prognosis with and without treatment cost
what will be considered when tailoring treatment to the individual case?
tumor biology
histology
grade
stage
what is the ideal aim of cancer treatment?
cure
what is involved in cancer cure?
all cells that have the capacity for tumor regeneration are eradicated
what is the more achievable treatment aim?
remission
what is remission?
all clinical evidence of cancer has disappeared
occult cancer cells remain and relapse will occur at some point
what is the aim of palliative cancer treatment
reduce pain / improve sense of well being and / or correct physiological malfunction
what is usually chosen when deciding on cancer treatment for pets?
best quality of life as opposed to greatest number of cures
what is the only method of treatment likely to affect a cure for cancer?
complete surgical excision
what are the 3 main methods of cancer treatment in animals?
surgical excision
radiation
chemotherapy with anti cancer / cytotoxic drugs
how are most cancer treatment modalities used except for systemic cancers?
modalities combined
how can cancer treatment modalities be combined to treat cancer?
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
what is the most effective treatment for the majority of solid tumors?
surgery
what is local excision “lumpectomy” suitable for?
truly benign tumor (fibroma, lipoma, benign mammary tumor)
what is involved in a wide local excision of a tumor?
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
what is wide local excision suitable for?
basal cell carcinoma
squamous cell carcinoma
mast cell tumor
when is wide local excision more challenging?
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
what tumors infiltrate adjacent tissues more widely than 1-2cm margins?
soft tissue sacromas
what does resection of tumors infiltrating more than 1-2cm of local tissues involve?
removing every tissue compartment which the tumor involves
what is the resection involving removing every tissue compartment which the tumor involves called?
en bloc or compartmental resection
what is often needed to close the wound after en bloc resection?
reconstructive procedures
when does failure of surgical tumor excision occur?
regrows at the primary site due to incomplete resection
metastasis has already occurred
tumor is systemic
what is regrowth of a tumor at the primary site due to?
site involving vital structures that cannot be removed
infiltration of tumor due to inadequate margins
what is surgical debulking?
removal of as much of a surgically incurable malignant tumor as possible
what is surgical debulking followed by?
subsequent therapy (e.g. drugs, radiation)
what are the general rules of surgical tumor resection?
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)
what is the purpose of 2 sets of instruments for excision and closure in cancer surgery?
prevent iatrogenic tumor seeding
how should the form for biopsy samples to an external lab be filled in?
provide history
mark particular margin with ink if there are concerns
identify and orientate samples with labels
submit all samples and entire tumor
what are the general considerations for post op management of cancer patients?
nutrition
analgesia
wound care/management
rehab needed to regain functionality
what is the effect of excessive tension on a wound?
compromise of circulation slow wound healing wound breakdown necrosis distortion of anatomic areas
what does tension over an artery lead to?
ischaemia
what does tension of a wound over veins and lymphatics do?
lead to oedema
what are the 2 main factors in wound breakdown?
patient factors
wound factors
what are the patient factors which affect wound healing?
intrinsic - concurrent disease, nutrition
extrinsic - chemo, steroids, radiotherapy
what are the wound factors that can lead to wound breakdown?
neoplasia tissue handling/haemostasis tension motion sutures infection patient interferance
what should happen if wound breakdown occurs?
manage wound
do not resuture
allow to heal via second intention
what is a surgical wound that breaks down classed as?
dirty wound
how should wounds that suffer wound breakdown be allowed to heal?
via second intetion
what is seroma?
accumulation of fluid at the level of a wound
how can seroma formation be prevented?
reduce dead space
place drains
rest
how should seroma be treated?
can leave to recover alone
pressure bandage placed
provide further drainage
how should wound infection be treated?
drainage
allow to heal via second intention
antibiotics based on culture and sensitivity
exploration of wound if necessary
what is radiation oncology?
the medical use of ionising radiation as an integral part of cancer treatment by killing or controlling malignant cells
what is radiation most effective for?
local treatment following incomplete surgical excision of tumor
how does radiation work?
ionisation - removal of an orbiting electron from the shell of an atom
what are the 2 main methods for application of radiation to patients?
brachytherapy
external beam radiation therapy or teletherapy
what is the most common form of radiation therapy used in veterinary practice?
external beam radiation therapy or teletherapy
what are the 2 types of radiation used in radiation therapy?
electrons (beta particles) - easily shielded
high energy x-rays (harmful)
how does brachytherapy work?
radioactive substance emits gamma rays or beta particles close to tumor
how is brachytherapy administered?
applied to tumor surface
implanted within tumor (seeds)
administered systemically but concentrated on tumor
how does external beam radiation therapy or teletherapy work?
radiation therapy given by an external radiation source at a distance from the body
what is the most commonly used method of external beam radiation therapy or teletherapy?
LINAC - linear accelerator
how is external beam radiation therapy or teletherapy dosed?
multiple fractions (doses) given over 4-6 weeks
why is external beam radiation therapy or teletherapy limited?
restricted availability of fixed radiation source or LINAC
what are the acute side effects to radiation therapy?
erythema vesiculation desquamation severe exfoliative dermatitis localised hair loss
what are the late toxicity side effects of radiation therapy?
depigmentation
dermal fibrosis
osteonecrosis
neural necrosis
what is chemotherapy?
the use of chemicals to destroy infective agents
why are risk assessments for chemotherapy necessary?
drugs are highly toxic and potentially dangerous to vet, support staff and owners
what does tumor response to chemotherapy depend on?
growth fraction
what cells are most susceptible to chemotherapy?
rapidly dividing
when are tumors more sensitive to chemotherapy?
early stages of development where they are rapidly growing and dividing
when are tumors less susceptible to chemo or radiation?
when they are detectable and growing more slowly
what are chemotherapy drugs most effective against?
rapidly growing or dividing cells
what are the rapidly dividing cells found in the body during chemo?
cancer cells
bone marrow
GI tract
what do chemotherapy drugs act upon?
processes in cell growth and division (e.g. DNA replication and metabolic activities)
what does response to chemotherapy depend on?
tumor growth rate
drug resistance
how should a chemo dose be chosen?
highest possible dose to affect maximum fractional kill with minimum side effects
i.e. the dose with maximum acceptable side effects
when is chemotherapy ideally used?
when tumor burden is at it’s lowest and growth fraction highest
when is tumor burden likely to be at it’s lowest and growth fraction highest?
early on or after surgical debulking
what regime is used to give chemotherapy?
repeated doses of a range of drugs allowing recovery time
typically 3 week cycles
how is chemotherapy dosing calculated?
function of surface area in metres squared
what neoplasia is typically highly sensitive to chemo?
lymphoma
myeloma
some forms of leukaemia
what neoplasia typically has moderate sensitivity to chemo?
high grade sarcomas
mast cell tumors
what neoplasia is typically poorly sensitive to chemotherapy?
most slow growing sarcomas
most carcinomas
melanomas
what is the favoured approach in chemotherapy?
combination therapy
what is combination therapy?
combine different classes of chemotherapy agents with different mechanisms of action and different side effects?
what is the benefit of combination chemotherapy?
combinations are more effective than a single agent greater tumor kill is achieved less resistance fewer side effects may be better tolerated
what are chemotherapy protocols often named after?
the agents used
what is the common feline chemo regime for lymphoma?
C (cyclophosphomide)
O (Oncovin)
P (prednisolone)
what is the common canine chemo regime for lymphoma?
C (cyclophosphomide)
H (hydroxydaunorubicin - doxorubicin)
O (Oncovin)
P (prednisolone)
what is chemotherapy used as a first line treatment for?
diseases that are systemic in nature (surgery non-curative or possible)
why do systemic cancers normally respond well to chemotherapy?
high growth fraction
what cancers is first-line chemotherapy used to treat?
lymphoma
some forms of leukaemia
multiple myloma
what is adjunctive chemotherapy used for?
solid tumors where chemo would not be of value as the sole therapy
what cancers are often treated with adjunctive chemotherapy?
carcinoma
sarcoma
what is the main aim of chemotherapy as an adjunct to surgical and/or radio therapy?
reduction of tumor mass to enable surgical resection
try to prevent / delay metasiasis
what is metronomic chemotherapy?
palliative low doses of chemotherapy drugs
how often is metronomic chemotherapy given?
daily
what is the target of metronomic chemotherapy?
endothelium or tumor stroma
what is the effect of targeting tumor stroma in metronomic chemotherapy?
anti-angiogenic to slow tumor growth
what is the aim of metronomic chemotherapy?
minimise toxicity and palliation
slows disease progression
what is chemoembolisation?
local, directed delivery of chemotherapy drug and embolization to treat inoperable solid tumors
where is chemo applied during chemoembolisation?
injected into blood vessel that supplies the tumor via fluroscopy
how is chemoembolisation performed?
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
what is involved in the safe use of chemotherapy?
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
what are the safety precautions that should be taken when handling cytotoxic drugs?
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
what is involved in the nursing care of patients receiving chemotherapy with regards to management of cytotoxic waste?
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
what is the risk period following chemo drug administration?
time when cytotoxic material may be found in patients waste - varies between drugs
how should chemotherapy patients be managed at home to ensure that owners are kept safe?
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
what should be done after washing chemo patients laundry?
machine should be put on an empty washing cycle before any other laundry is washed
how should urine, faeces and vomit from a chemo patient be cleaned up?
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
what are chemo dosages chosen usually a compromise between?
efficacy and safety
what are the inherent toxicities of all chemotherapy agents due to?
effect on dividing cells
what healthy cells are most affected by chemotherapy?
normal tissues with high cell turnover (e.g. bone marrow and GI tract) which will recover faster than tumor
what causes the direct GI toxicity of chemotherapy?
death and loss of intestinal epithelial cells
when does GI toxicity due to chemo usually occur?
5-10 days after drug administration
what are the main signs of GI toxicity due to chemo?
stomatitis
vomiting
mucoid or haemorrhagic diarrhoea
what can cause early nausea and vomiting in chemo patients?
drugs may induce early nausea and vomiting by stimulation of CRTZ (chemoreceptor trigger zone)
how is GI toxicity due to chemo treated?
symptomatic
IVFT
anti-emetics
gastro-protectants for any gastric ulceration
parenteral antibiotics if haemorrhagic diarrhoea or immunosuppressed
what coat changes are seen in chemo patients?
cats usually only loose whiskers
not a problem in most dogs
does coat loss occur in dogs due to chemotherapy?
some breeds are susceptible to significant hair loss leading to a patchy coat
what may happen to the coat of an old English sheepdog following chemotherapy?
coat may regrow in a different colour
what is myelosuppression?
damage and suppression of bone marrow
what must be performed before any chemotherapy?
haematology to check WBC
when may chemo be delayed or reduced following haematology?
if there is mylosuppression
what does myelosuppression cause?
neutropenia (life threatening)
thrombocytopenia
anaemia
what is the patient at risk of if the neutrophil count is <2 x 10^9 per L?
sepsis from translocation of enteric bacteria
what does management of neutropenia depend on?
absolute cell count
clinical signs
why does translocation of enteric bacteria occur?
enterocytes damaged by chemo
gut becomes more leaky
low neutrophils reduces ability to fight infection
what is the recommended action if there is no neutropenia (>3)?
continue chemo
repeat WBC before next chemo dose
what is the recommended action if there is mild neutropenia (2-3)?
reduce dosage by 50%
repeat WBC count 10-14 days post treatment admin
what is the recommended action if there is moderate neutropenia (<2)?
stop chemo
monitor patient and WBC
avoid hospitalisation
administer antibiotics if patient is predisposed to infection
why should moderately neutropenic patients not be hospitalised?
infection risk is higher in hospital
what is the recommended action if there is severe neutropenia (<1) but patient is asymptomatic / afebrile?
stop all cytotoxic treatment
antibiotics
collect samples for culture
what is the recommended action if there is severe neutropenia (<1) and the patient is sick / pyrexic?
stop all cytotoxic treatment
hospitalised
IV fluids given
bacteriocidal antibiotics
what is neutropenia an indication of?
maximum tolerated dose being reached / approched
what may myelosuppression be associated with?
better prognosis as maximum tolerated dose is being used
when is hypersensitivity / anaphylaxis to chemo seen?
rare but reported in dogs with doxyrubicin
what should you do if hypersensitivity or anaphylaxis reaction to chemo occurs?
IVFT
soluble corticosteroids
adrenaline
antihistamines
when may phlebitis or tissue necrosis occur?
if topical or extravasate (outside vein)
what are the 2 main types of chemo drugs that can cause phlebitis or tissue necrosis?
irritants
vesicants
what can irritant chemo drugs cause?
local inflammatory reactions at infusion site e.g. swelling, pain
what can vesicant chemo drugs cause?
severe and/or irreversible tissue injury and necrosis
what are 2 common vesicant chemo drugs?
Vincristine
Doxorubicin
what can be done to reduce the risk of extravasation?
drugs in sealed system
adequate patient restraint
clean stick IV catheter used for administration
catheter flushed before and after
how is perivascular leakage of doxorubicin treated?
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
what is used for Vincristine extravasation?
warm compress
DMSO
what is the antidote for extravasated doxorubicin?
dexrazoxane
what are some specific drug toxicities?
sterile haemorrhagic cystitis
cardiotoxicity
hepatotoxicity
nephrotoxicity
what causes sterile haemorrhagic cystitis?
metabolites of cyclophosphomide in the urine which have an irritant effect on the bladder leading to cystitis
what drug is associated with sterile haemorrhagic cystitis?
cyclophosphomide
what are the signs of sterile haemorrhagic cystitis?
profuse haematuria
how can sterile haemorrhagic cystitis be treated?
no specific treatment
sometimes irreversible
MESNA may be protective
how can risk of sterile haemorrhagic cystitis be minimised?
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
what chemo drug causes cardiotoxicity?
doxorubicin
what can acute cardiotoxicity from doxorubicin lead to ?
tachyarrhythmias
how can acute cardiotoxicity due to doxorubicin be prevented?
slow infusion over at least 15 mins
monitor pulse
wha
how is chronic cardiotoxicity from doxorubicin prevented?
don’t give more than the cumulative dose of 240 mg/metres squared over 8 doses
what chemo drug causes hepatotoxicity?
lomustine (CCNU)
what is the sign of hepatotoxicity due to lomustine?
increase in liver enzymes
when should lomustine treatment be delayed or discontinued?
if liver enzymes are 3x upper reference range
how can hepatotoxicity due to lomustine be prevented?
coadministration with SAMe
monitor biochemistry before each treatment
how is nephrotoxicity caused in chemo patients?
platinum compounds cause necrosis of proximal tubular cells
how can nephrotoxicity in chemo be prevented?
administer drugs slowly with IVFT diuresis
monitor urea/creatinine
