Oncology

Question 1

What hormone does Sertoli cell tumors secret?

Answer 1

Estrogen

Question 2

Name 4 lab abnormalities of acute tumor lysis syndrome. When does it usually occur?

Answer 2

Hyperkalemia
Hyperphosphatemia
Hypocalcemia
Hyperuricemia

48 hours after chemotherapy
* purines (adenine and guanine) are released and converted to uric acid via the purine degradation pathway and excreted in the urine

Question 3

Name 4 neoplasia that is associated with polycythemia.

Answer 3

Renal carcinoma
Renal lymphoma
Nasal fibrosarcoma
Renal fibrosarcoma

• Paraneoplastic polycythemia may be due to excessive EPO production by the tumor, kidney hypoxia with subsequent EPO release, production of an EPO-related hormone, or changes in EPO metabolism.

Question 4

What is the proposed pathophysiology for neoplasia-associated hypertrophic osteopathy?

Answer 4

1) Release of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF)
2) Afferent neurological stimulation
3) Increased circulating vasodilators

Question 5

Describe the emergency management of doxorubicin extravasation.

Answer 5

1) Stop the infusion and perform immediate aspiration through the displaced IV catheter to remove as much extravasated drug as possible
2) Administer dexrazoxane in 3 to 6 hours after the extravasation event, follow by subsequent dosing at 24 and 48 hours after extravasation.
* Doses range from 300 (or 10 times the doxorubicin dose) to 1000 mg/m2 IV
3) Cold compress
4) Treat any local reaction symptomatically with topical preparations (e.g. topical dimethyl sulfoxide
(DMSO)), bandaging, Elizabethan collar, and surgical debridement if severe. 


• Dexrazoxane
• an iron chelator that prevents anthracycline-iron complexes and free radical formation causing oxidative damage
• protective effect on healthy tissue by stabilizing topoisomerase II, thereby preventing damage from anthracycline.

Question 6

Describe the emergency management of vincristine extravasation.

Answer 6

1) Stop the infusion and perform immediate aspiration through the displaced IV catheter to remove as much extravasated drug as possible
2) infiltrate the area with sterile saline or with sterile saline and 8.4% sodium bicarbonate and 4 mg
dexamethasone sodium phosphate
* Give hyaluronidase
3) Warm compress
4) Treat any local reaction symptomatically with topical preparations (e.g. topical dimethyl sulfoxide
(DMSO)), bandaging, Elizabethan collar, and surgical debridement if severe.

Question 7

What is the timeframe for neutropenia development in the following chemotherapeutic agents?
- Vinblastine and paclitaxel
- Doxorubicin and cyclophosphamide
- Cisplatin
- Carboplatin

Answer 7

Vinblastine and paclitaxel: 4 – 5 days
Doxorubicin and cyclophosphamide: 7 – 10 days
Cisplatin: 7 – 16 days
Carboplatin: 2 – 3 weeks

Question 8

What specific toxicity can the following chemotherapeutic agents cause?
- Lomustine (CCNU)
- Cyclophosphamide
- Doxorubicin
- Chlorambucil
- Cisplatin

Answer 8

Lomustine (CCNU) - hepatotoxicity (cumulative dose)
Cyclophosphamide - sterile hemorrhagic cystitis
Doxorubicin - irreversible cardiotoxicity (cumulative dose; present as DCM with decreased LV systolic function)
Chlorambucil - neurotoxicity
Cisplatin - nephrotoxicity (dog); pulmonary edema and death in cats (don’t use in cat!!!)

Question 9

Name 4 categories of antimicrobial resistance.

Answer 9

1) Efflux pump
2) Modification of drug targets
3) Inactivation of a drug
4) Limit uptake of a drug