Lecture 9 - Antineoplastic Agents Flashcards
name a cancer that does not form a tumor mass
leukemia
list some factors that are suggested as contributing to causing cancer
- life style factors (smoking, diet)
- genetic factors (oncogenes, defective tumor-suppressor genes)
- environmental factors (UV radiation, pollution)
- chemical factors (asbestos, some medications)
- viruses (ex. HPV causes cervical cancer)
what do high numbers in staging mean
indicates more extensive, serious disease and a poorer prognosis
AJC staging
stave 0-IV
TNM system
T = tumor size (0-4) N = lymph node involvement (0-3) M = metastases (0-1)
common treatments for cancer
- surgery
- radiation therapy
- chemotherapy
surgery may be necessary to determine what?
- tumor size
- extent of metastases to determine staging or prognosis
Describe radiation
the use of ionizing radiation to kill cancer cells and reduce tumor mass
What is the goal of radiation?
to harm as many cancer cells as possible while limiting damage to the surrounding healthy tissues so it is given in many sessions to allow the healthy tissue to recover between sessions
Radiation can be used to treat most solid tumors including ?
those of the brain, breast, lung, cervix and stomach
What does the amount of radiation used depend on?
- type of cancer
- proximity of sensitive tissues or organs
- constitution of the patient (i.e. how healthy the patient is)
What is chemotherapy?
- involves treatment with drugs which can destroy cancerous cells
- chemotherapy usually refers to the use of cytotoxic drugs which affect rapidly dividing cells in general (so chemotherapy will also harm healthy tissues, especially those with a high replacement rate like the lining of the intestine)
- although these drugs are not specific for cancerous cells, some specificity is achieved since normal cells are able to repair DNA damage while cancerous cells usually cannot.
Why is combination chemotherapy used?
- to achieve synergy between some of the patients
- to reduce the possibility of resistance developing
- to reduce dose-related adverse effects
Chemotherapy drugs are usually administered under a plan known as a _____
protocol
What does the protocol define?
- drugs and doses used
- clinical monitoring required
- clinical endpoints as well as contingency plans (plan B) to be used as indicated by the patient’s progress and monitored parameters
Most drug doses are based on ______ _____ ____
body surface area
What are most common routes of admin of chemotherapy?
- IV
- oral
- sometimes intrathecal route is used in order to get the agent across the BBB but this route is absolutely CI for a number of antineoplastic drugs most notably the Vinca alkaloids
Vinca alkaloids never administered through ______ route
intrathecal
why might oral be better than IV
-pt can be at home, decreases costs and side effects
what are some common groups of drugs related to managing the symptoms of cancer
- antiemetics
- analgesics
- hematopoietic growth factors
what’s the difference between side effects and adverse effects?
Side effects: we can explain it based on receptor binding
Adverse effects: don’t know why it happened, come out of nowhere
how do alkylating agents work?
inhibit DNA replication by causing cross-linking and abnormal base pairing of the DNA strands.
prototype agent of alkylating agents
mechlorethamine or nitrogen mustard
alkylating agents are quite ____
toxic
How can cancer cells become resistant to alkylating agents?
through increased ability to repair DNA lesions, decreased permeability to the agents or increased production of glutathione which reads with the alkylating agent
why do we do cancer treatment in cycles
to allow the body to recover
What are adverse effects seen with alkylating agents?
- myelosuppresion with granulocytopenia
- thrombocytopenia
- anemia
- nausea/vomiting
- alopecia (reversible)
List some alkylating agents
a) nitrogen mustards (cyclophosphamide)
b) alkyl sulfonates (busulifan)
c) nitrosureas (carmustine, lomustine)
d) triazenes (dacarbazine)
What are Antimetabolites?
Structural analogues of naturally occurring substrates for biochemical reactions occurring in the body.
Several of them act as false substitutions in the production of nucleic acids and interrupt and stop the replication process.
List some antimetabolites
a) Folic acid analogs (methotrexate)
b) Purine analogs (mercaptopurine)
c) Pyrimidine analogs (%-FU, cytabarine)
Describe antibiotics for cancer treatment
Most of the antitumor antibiotics are obtained form Streptomyces species through fermentation process.
These agents act by intercalation or by sliding between DNA base pairs and inhibiting DNA synthesis.
List some examples of antitumor antibiotics
a) Anthracyclines (epirubicin, doxorubicin)
b) Miscellaneous (bleomycin, dactinomycin, mitomycin)
Describe Vinca alkaloids
The vinka alkaloids prevent formation of the mitotic spindle and stop cell division
List some plant alkaloids
a) Vinca alkaloids (vinblaastine, vincristine, vindesine)
b) Podophyllotoxins (Etoposide, teniposide)
c) Taxanes (docetaxel, palictaxol)
Describe the podophyllotoxins
; the podophyllotoxins inhibit topoisomerase an enzyme that is necessary for RNA transcription
Describe the Taxanes
The taxanes stabilize microtubules thereby prohibiting cell division
List some hormones that can be used in chemotherapy
a) Androgens (Testosterone)
b) Antiandrogen (Flutamide)
c) Estrogens (diethylstilbestrol)
d) Anti-estrogens (Tamoxifen)
e) Corticosteroids (dexamethasone, prednisone)
Describe platinum compounds
These drugs act in a similar manner as the alkylating agents and the group includes cisplatin and carboplatin
Cells with high turnover rates are more sensitive to chemotherapy toxicity. List some examples
- bone marrow
- mucous membranes
- hair follicles
- therefore the most common toxicities include myelosuppresion, mucositis and alopecia
- these are considered acute and self-limiting
myelosuppression is also known as ?
bone marrow suppression
The extent of myelosuppresion is ____-related
dose