Cancer Chemotherapy Flashcards
Complications with cancer treatments
- Cure requires 100% killing of cancer cells
- 1st order cell killing-depend on t1/2
- little involvement in host defenses
- signs/symptoms improper quiz it
- drug resistance
- heterogeneity of tumor cells
- limited access to some tumors-physiological barriers
- why curing with drug therapy is very difficult
Cancer growth pattern
Differs patient to patient and cancer to cancer
- how many cancer cells are in the body vs the realization of signs and symptoms
- flat curve (# of cancer cells vs time)
To improve drug response:
Intermittent chemo (in bursts) less likely to develop resistance
Combination therapy: ⬇️ resistance, ⬆️ clinical response, ⬇️ in toxicity
Route of administration- for difficult to treat cancers (brain)
Drug related toxicities- apply to all cytotoxic drugs
-tissues w/ high growth fraction at high risk: target rapidly dividing cells
-bone marrow, hair, GI, skin
#1 reason why therapy fails- side effects are too much for patients to handle
1) bone marrow suppression (myelosupression)
- RBC, WBC, platelets
*neutropenia: ⬇️ in WBC, high risk of severe infection, all signs may be absent besides fever (Tx ASAP)
Nadir- when ⬇️ in WBC count is at the worst (10-14 days/recovery 1 week) or delayed (3-4 week/recover at wk 7)
*thrombocytopenia: when platelets ⬇️, high risk of bleeding/bruising
*anemia: ⬇️ in RBC
To treat nuetropenia, thrombocytopenia and anemia (growth factors):
Nuetropenia: Filgrastim, Pegfilgrastim, sagramastim ( ⬆️ WBC production by bone marrow)
Thrombocytopenia: oprelvekin (stimulates platelet formation)
Anemia: epietinalfa, darbepoeitin (erythropoietin)- stimulates RBC production
- by themselves don’t Rx cancer, only reduce the side effects of other drugs
- antidotes for (cytotoxic) chemotherapy
Drugs that vary in degree of causing myelosupression:
⬇️ risk: streptozocin, bleomycin, vincristine
Delayed: carmustine, lomastine, mitomycin
2) GI tract injury
- stomatitis: damage/inflammation/ulcers to oral mucosa
- good oral hygiene/ mouthwash
- palifermin (kepivance)- antidote for stomatitis, only used for hematologic cancer (lymphoma, leukemia)
- diarrhea: loperamide, diphenooxylate
3) nausea/vomiting (CIMV)
-major treatment related problem
-dehydration, electrolyte imbalance
#1 reason why people refuse treatment
-direct stimulation of CTZ/vomiting center
*3 drug combo to treat CIMV, short term at beginning of chemo
*aprepitant/fosaprepitant, Dexamethasone, 5-HT3 antagonist
4) other related toxicities
- alopecia (hair loss)
- reproductive toxicity
- hyperurecemia: ⬆️ Uric acid conc from DNA breakdown
- will damage kidneys
- monitor renal fxn/Uric acid levels
- antidote for ⬆️ Uric acid levels: allopurinol, rasburicase (injectable/short term), pegloticase (gout/long term)
5) direct injury to skin, veins and tissues
- vesicant: blister causing (anthracyclines, acitonomycin D, mitomycin, nitrogen mustards, taxanes
- concern with needle poking thru the veins- will cause damage to the tissues* (extravasation)
- cool the site with ice pack
- “vincas” heat the site
Two treatments for cancer?
1) general cytotoxic drugs (classic chemo)
2) targeted therapy
Alkylation agents Antimetabolites Anti-tumor antibiotics Mitotic inhibitors Topoisomerase inhibitors Miscellaneous agents
Cytotoxic drug “classes”
*cyclophosphamide, isophosphamide
*streptozocin
*procarbazine
*busulfan
*cisplatin
*oxilplatin
Melphalan
Lomustine
Temozolomide
Mechlorethamine
Bendamustine
Thiotepa
Dacarbazine
Altretamine
Chloramubucil
Carmustine
Alkylating agents: cytotoxic drugs
Alkylating agents: miscode/break DNA
Antimetabolites: inhibit DNA/RNA protien synthesis
Topoisomerase inhibitors: inhibit topoisomerase/ damage DNA
Mitotic inhibitors: interfere with normal microtubule fxn
Cytotoxic agents MOA
