Oncology Flashcards
what causes cancer?
it is mulifactorial
- genetic mutations in DNA that result in defective regulatory circuits of a cell
- lifestyle and environment: diet, exposure, viruses, age
what is the mechanism of cancer? (steps)
- initiation: induce DNA damage
- promotion: reversible tissue and cellular changes
- progression: irreversibly convert an initiated cell into a cell exhibiting malignancy
what are the 6 hallmarks of a cancer cell?
- evading apoptosis
- self-sufficiency in growth signals
- insensitivity to anti-growth signals
- tissue invasion and metastasis
- limitless replicative potential
- sustained angiogenesis
what are the three cell types cancer comes from ?
round, mesenchymal and epithelial cells
what are the differentials for a round cell cytopathology ?
Please Help Me Learn This
- plasmacytoma
- histiocytoma
- melanoma
- lymphoma
- tvt
what are the differentials for a mesenchymal cell cytopathology ?
sarcomas
what are the differentials for an epithelial cell cytopathology ?
carcinomas
what type of cell will be spindle shaped on cytology?
mesenchymal cells
what type of cell has very good exfoliation on cytology ?
round cells
what type of cell is round and arranged in sheets on cytology?
epithelial cells
what characteristics of malignancy do we look for?
- homogenous vs. heterogeneous
- monomorphic vs. pleomorphic
- cellular/cytoplasmic criteria like anisocytosis or hyperchromasia
- nuclear criteria ** - anisokaryosis, multiple nucleoli, increased mitosis
what is an advantage and disadvantage of cytopathology?
highly specific but low sensitivity
what is the exception to remember with needle tract implantation?
urogenital neoplasms
what do we associate multiple similar nodules on splenic ultrasound with?
significantly associated with malignancy
what method do we use when performing cytology of spleen?
non-aspirate technique due to less blood contamination
true or false.
ultrasound guided cytology of GI tumors is not specific.
false. highly specific almost 100%
when performing a cytology of bone tumor if we get a positive ALP stain, what is the interpretation?
100% sensitive for OSA
true or false.
we can determine a grade of a tumor based on cytology.
false, need a block of tissue to determine
does staging or grading determine if tumor is localized or has spread?
staging
does staging or grading determine the aggressiveness of tumor ?
grading, grade 1-3
what are some classic staging tests?
- CBC/CHEM (min. database)
- regional lymph node cytology
- THREE view thoracic met check
- abdominal ultrasound
- CRT or MRI
what is locoregional lymph node sampling based on?
sentinel node
- first lymph node in the drainage of nodes to drain tumor
true or false.
the sentinel lymph node is always the draining lymph node
false
true or false.
if the lymph nodes are normal sized we can assume they are not metastatic.
FALSE, never assume this
how many views of thoracic radiographs should we take when staging?
ALWAYS THREE
- can miss 12-15%of mets if you only do a 2 view study
what is the minimum threshold size required to reliably detect nodules on rads
7-9 mm
if we have a facial tumor do we need to perform an abdominal ultrasound?
yes, the liver is the most common receptacle for blood borne metastasis so need to confirm there are no mets
true or false.
paraneoplastic syndromes are often the first sign of malignancy but aren’t hallmarks of malignancies.
false. often the first sign of malignancy and can be a hallmark of malignancy
what are some examples of a classic paraneoplastic syndrome ?
- anal sac adenocarcinoma - hypercalcemia
- thymoma/myasthenia gravis - neurologic
- intestinal leiomyosarcoma - hypoglycemia
what are the 2 goals of conventional chemotherapy?
- enhance or maintain quality of life and family bond
2. stabilize, diminish or eliminate neoplastic process
what types of cells does chemotherapy drugs target?
all rapidly dividing cells
- tumor cells but also GI, bone marrow and hair
what does fractionation of dosing do?
allows recovery of normal tissue between treatment intervals
why do we use a neoadjuvant ?
used prior to treatment for things like attempting to shrink the tumor
when determining dose of chemo drugs what do we base dose on?
dosage is based on toxicity rather than efficacy, we determine the maximum tolerated dose
what is the maximum tolerated dose?
a dose that produces an “acceptable” level of toxicity
what accounts for a large amount of mistakes with chemotherapy dosing ?
dose calculation errors!
- have 2 people do calculation
what are the drugs that have an increased risk due to the MDR 1 gene?
vincristine, vinblastine, paclitaxel and doxorubicin
what PPE should we use with chemo drugs?
gloves, gowns, face masks
what is something we should inform owners of when they have a pet undergoing chemo treatments ?
- to wear gloves when cleaning up after pet for the first 48 hours after drug administration
- never crush or split pills
what are the most common adverse events with cytotoxic chemotherapy?
BAG!
- Bone marrow suppression (most common)
- Alopecia (non-shedding breeds only)
- Gastrointestinal
true or false.
in order to give chemo, the neutrophil count needs to be 3,000 or higher and platelet count needs to be 100,000 or higher.
true
how do we monitor patient after we give the chemo drugs?
recheck CBC at the NADIR which is usually 5-10 days
usually recheck CBC at 7 days post chemo and compare with CBC results from before chemotherapy was given
what is the NADIR?
the expected low point of bone marrow insult
if the neutrophil count at nadir is below 1,500 or the platelet count is below 60,000, what do we do?
reduce the subsequent doses by 20-25%
what happens when we reduce the dose 20%?
the efficacy of the therapy is reduced 50%
how do we try to control the side effects of myelosuppression in chemo patients?
- use prophylactic antibiotics to avoid systemic infections (want 4 quadrant coverage)
- avoid sources of infection like park, groomers, raw diets, etc.
- keep in ICU in severe cases
what chemotherapy drugs are cell-cycle specific?
antimitotics and antimetabolites
what chemotherapy drugs are cell-cycle non-specific?
alkylating agents and antibiotics
what is the mechanism of action of antimitotics?
immobilize the mitotic spindle which is necessary for cell division
what should we do if vincristine (antimitotic) extravasates ?
warm it up! need to disperse and dilute
what chemotherapy drug can result in a neuropathy?
vincristine
what is the mechanism of action of alkylating agents?
changes the structure of DNA and interferes with transcription, replication and repair machinery
what chemo drug is associated with sterile hemorrhagic cystitis ?
cyclophosphamide
what chemo drug is liver toxic and what should we give in conjunction with it?
- lomustine or CCNU
- give with denamarin because it is hepatoprotective
what chemo drug is related to dose-related cardiotoxicity ? what should we do to prevent it?
- doxorubicin
- prescreen boxers/dobermans with an echo
what chemo drug is also called “red death”?
doxorubicin
what chemo drug is also called “blue thunder”?
mitoxantrone
what chemo drug can cause tinnitus ?
doxorubicin
if doxorubicin extravasates, what should we do?
DON’T disperse!
use ice to localize and neutralize
what chemo drug is cardiac sparing?
mitoxantrone
what is the mechanism of action of antimetabolites ?
effects the S phase
what is the mechanism of action of platinum agents ?
covalent binding to DNA strands and forms interstrand cross links
can we give cisplatin to cats?
NOOOO - splats cats!
why does cisplatin splat cats?
fatal pulmonary edema
can we give L-asparaginase IV?
no, causes a hypersensitivity reaction
true or false.
cisplatin causes nephrotoxicity.
true
can you give carboplatin to cats?
yes this one is okay, DONT give cisplatin
what is metronomic chemotherapy?
revolves around the concept of eliminating break period by giving low dose continuous chemotherapy
what are pros and cons of metronomic chemotherapy?
pro - lower toxicity
con - not cytotoxic
what are the MOAs of metronomic chemotherapy ?
- antiangiogenesis
- immunomodulation
- direct targeting
