Oncology

Question 1

what causes cancer?

Answer 1

it is mulifactorial

• genetic mutations in DNA that result in defective regulatory circuits of a cell
• lifestyle and environment: diet, exposure, viruses, age

Question 2

what is the mechanism of cancer? (steps)

Answer 2

• initiation: induce DNA damage
• promotion: reversible tissue and cellular changes
• progression: irreversibly convert an initiated cell into a cell exhibiting malignancy

Question 3

what are the 6 hallmarks of a cancer cell?

Answer 3

1. evading apoptosis
2. self-sufficiency in growth signals
3. insensitivity to anti-growth signals
4. tissue invasion and metastasis
5. limitless replicative potential
6. sustained angiogenesis

Question 4

what are the three cell types cancer comes from ?

Answer 4

round, mesenchymal and epithelial cells

Question 5

what are the differentials for a round cell cytopathology ?

Answer 5

Please Help Me Learn This

• plasmacytoma
• histiocytoma
• melanoma
• lymphoma
• tvt

Question 6

what are the differentials for a mesenchymal cell cytopathology ?

Answer 6

sarcomas

Question 7

what are the differentials for an epithelial cell cytopathology ?

Answer 7

carcinomas

Question 8

what type of cell will be spindle shaped on cytology?

Answer 8

mesenchymal cells

Question 9

what type of cell has very good exfoliation on cytology ?

Answer 9

round cells

Question 10

what type of cell is round and arranged in sheets on cytology?

Answer 10

epithelial cells

Question 11

what characteristics of malignancy do we look for?

Answer 11

• homogenous vs. heterogeneous
• monomorphic vs. pleomorphic
• cellular/cytoplasmic criteria like anisocytosis or hyperchromasia
• nuclear criteria ** - anisokaryosis, multiple nucleoli, increased mitosis

Question 12

what is an advantage and disadvantage of cytopathology?

Answer 12

highly specific but low sensitivity

Question 13

what is the exception to remember with needle tract implantation?

Answer 13

urogenital neoplasms

Question 14

what do we associate multiple similar nodules on splenic ultrasound with?

Answer 14

significantly associated with malignancy

Question 15

what method do we use when performing cytology of spleen?

Answer 15

non-aspirate technique due to less blood contamination

Question 16

true or false.

ultrasound guided cytology of GI tumors is not specific.

Answer 16

false. highly specific almost 100%

Question 17

when performing a cytology of bone tumor if we get a positive ALP stain, what is the interpretation?

Answer 17

100% sensitive for OSA

Question 18

true or false.

we can determine a grade of a tumor based on cytology.

Answer 18

false, need a block of tissue to determine

Question 19

does staging or grading determine if tumor is localized or has spread?

Answer 19

staging

Question 20

does staging or grading determine the aggressiveness of tumor ?

Answer 20

grading, grade 1-3

Question 21

what are some classic staging tests?

Answer 21

• CBC/CHEM (min. database)
• regional lymph node cytology
• THREE view thoracic met check
• abdominal ultrasound
• CRT or MRI

Question 22

what is locoregional lymph node sampling based on?

Answer 22

sentinel node

- first lymph node in the drainage of nodes to drain tumor

Question 23

true or false.

the sentinel lymph node is always the draining lymph node

Answer 23

false

Question 24

true or false.

if the lymph nodes are normal sized we can assume they are not metastatic.

Answer 24

FALSE, never assume this

Question 25

how many views of thoracic radiographs should we take when staging?

Answer 25

ALWAYS THREE | - can miss 12-15%of mets if you only do a 2 view study

Question 26

what is the minimum threshold size required to reliably detect nodules on rads

Answer 26

7-9 mm

Question 27

if we have a facial tumor do we need to perform an abdominal ultrasound?

Answer 27

yes, the liver is the most common receptacle for blood borne metastasis so need to confirm there are no mets

Question 28

true or false. | paraneoplastic syndromes are often the first sign of malignancy but aren't hallmarks of malignancies.

Answer 28

false. often the first sign of malignancy and can be a hallmark of malignancy

Question 29

what are some examples of a classic paraneoplastic syndrome ?

Answer 29

- anal sac adenocarcinoma - hypercalcemia - thymoma/myasthenia gravis - neurologic - intestinal leiomyosarcoma - hypoglycemia

Question 30

what are the 2 goals of conventional chemotherapy?

Answer 30

1. enhance or maintain quality of life and family bond | 2. stabilize, diminish or eliminate neoplastic process

Question 31

what types of cells does chemotherapy drugs target?

Answer 31

all rapidly dividing cells | - tumor cells but also GI, bone marrow and hair

Question 32

what does fractionation of dosing do?

Answer 32

allows recovery of normal tissue between treatment intervals

Question 33

why do we use a neoadjuvant ?

Answer 33

used prior to treatment for things like attempting to shrink the tumor

Question 34

when determining dose of chemo drugs what do we base dose on?

Answer 34

dosage is based on toxicity rather than efficacy, we determine the maximum tolerated dose

Question 35

what is the maximum tolerated dose?

Answer 35

a dose that produces an "acceptable" level of toxicity

Question 36

what accounts for a large amount of mistakes with chemotherapy dosing ?

Answer 36

dose calculation errors! | - have 2 people do calculation

Question 37

what are the drugs that have an increased risk due to the MDR 1 gene?

Answer 37

vincristine, vinblastine, paclitaxel and doxorubicin

Question 38

what PPE should we use with chemo drugs?

Answer 38

gloves, gowns, face masks

Question 39

what is something we should inform owners of when they have a pet undergoing chemo treatments ?

Answer 39

- to wear gloves when cleaning up after pet for the first 48 hours after drug administration - never crush or split pills

Question 40

what are the most common adverse events with cytotoxic chemotherapy?

Answer 40

BAG! - Bone marrow suppression (most common) - Alopecia (non-shedding breeds only) - Gastrointestinal

Question 41

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.

Answer 41

true

Question 42

how do we monitor patient after we give the chemo drugs?

Answer 42

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

Question 43

what is the NADIR?

Answer 43

the expected low point of bone marrow insult

Question 44

if the neutrophil count at nadir is below 1,500 or the platelet count is below 60,000, what do we do?

Answer 44

reduce the subsequent doses by 20-25%

Question 45

what happens when we reduce the dose 20%?

Answer 45

the efficacy of the therapy is reduced 50%

Question 46

how do we try to control the side effects of myelosuppression in chemo patients?

Answer 46

- 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

Question 47

what chemotherapy drugs are cell-cycle specific?

Answer 47

antimitotics and antimetabolites

Question 48

what chemotherapy drugs are cell-cycle non-specific?

Answer 48

alkylating agents and antibiotics

Question 49

what is the mechanism of action of antimitotics?

Answer 49

immobilize the mitotic spindle which is necessary for cell division

Question 50

what should we do if vincristine (antimitotic) extravasates ?

Answer 50

warm it up! need to disperse and dilute

Question 51

what chemotherapy drug can result in a neuropathy?

Answer 51

vincristine

Question 52

what is the mechanism of action of alkylating agents?

Answer 52

changes the structure of DNA and interferes with transcription, replication and repair machinery

Question 53

what chemo drug is associated with sterile hemorrhagic cystitis ?

Answer 53

cyclophosphamide

Question 54

what chemo drug is liver toxic and what should we give in conjunction with it?

Answer 54

- lomustine or CCNU | - give with denamarin because it is hepatoprotective

Question 55

what chemo drug is related to dose-related cardiotoxicity ? what should we do to prevent it?

Answer 55

- doxorubicin | - prescreen boxers/dobermans with an echo

Question 56

what chemo drug is also called "red death"?

Answer 56

doxorubicin

Question 57

what chemo drug is also called "blue thunder"?

Answer 57

mitoxantrone

Question 58

what chemo drug can cause tinnitus ?

Answer 58

doxorubicin

Question 59

if doxorubicin extravasates, what should we do?

Answer 59

DON'T disperse! | use ice to localize and neutralize

Question 60

what chemo drug is cardiac sparing?

Answer 60

mitoxantrone

Question 61

what is the mechanism of action of antimetabolites ?

Answer 61

effects the S phase

Question 62

what is the mechanism of action of platinum agents ?

Answer 62

covalent binding to DNA strands and forms interstrand cross links

Question 63

can we give cisplatin to cats?

Answer 63

NOOOO - splats cats!

Question 64

why does cisplatin splat cats?

Answer 64

fatal pulmonary edema

Question 65

can we give L-asparaginase IV?

Answer 65

no, causes a hypersensitivity reaction

Question 66

true or false. | cisplatin causes nephrotoxicity.

Answer 66

true

Question 67

can you give carboplatin to cats?

Answer 67

yes this one is okay, DONT give cisplatin

Question 68

what is metronomic chemotherapy?

Answer 68

revolves around the concept of eliminating break period by giving low dose continuous chemotherapy

Question 69

what are pros and cons of metronomic chemotherapy?

Answer 69

pro - lower toxicity con - not cytotoxic

Question 70

what are the MOAs of metronomic chemotherapy ?

Answer 70

- antiangiogenesis - immunomodulation - direct targeting