anti-cancer Flashcards
primary chemotherapy
primary tx in pt with adv CA without alternative tx possible
neoadjuvant chemo
given before sx. goal is to dec size of primary tumor so surgical resection can be made easier
adjuvant chemo
after local tx modalities (surgery) has been perforemd.
destroyed microscopic cells that may be present after local tx modalities.
dec incidence of both local and systemic recurrence and improve overall survival of pt
site directed chemo
direct instillation - into sanctuary sites
regional perfusion - of tumor
log kill hypothesis
action of cytotoxic drugs follows FIRST ORDER KINETICS
given dose kills a constant fraction of tumor cell population (rather than constant number)
repeat doses are required to eradicate
common AE
nausea/vomiting
stomatitis
alopecia
myelosupression (tx with filgrastim)
drugs with STRONG myelosuppression
cytarabine alkylating agents doxorubicin danunorubicin vinblastine
drugs with MODERATE myelosuppression
carboplatin
MTX
5-FU
drugs with MILD myelosuppression
bleomycin
vincristine
asparaginase
which drug causes cardiotoxicity
doxorubicin
which drug(s) causes hemorrhagic cystitis
cyclophosphamide
ifosphamide
which drug causes pulmonary fibrosis
bleomycin
which drug is most likely cause cause tx-induced neoplasms
aklylating agents
which drug rescues BM from MTX
leucovorin
which drug reduces hemorrhagic cystitis caused by cyclophosmaide and ifosfamide
mesna
which drug reduces anthracycline-induced cardiotoxicity
dexrazoxane
which drug reverses neutropenia caused by many anti-CA agents
filgrastim
which drugs is a cytoprotective agent that reduces renal toxicity cauesd by cisplatin
amifostine
primary resistance
no response to drug on first exposure
acquired resistance - single drug resistance
due to inc expression of 1 or more genes
acquired resistance - MDR
emerges to several drugs after exposure to a single agent
cell cycle specific vs cell cycle nonspecific drugs
specific: exert action only on cells traversing cell cycle
nonspecific: exert action whether they are cycling or resting in G0
what is more effective in hematological malignancies: cell cycle specific or nonspecific
cell cycle specific - assoc with high growth fraction
what is more useful in solid tumors with low growth fraction: cell cycle specific or nonspecific
nonspecific
cell cycle specific drugs
antimetabolites microtubule inhibitors epipodophyllotoxins camptothecins bleomycin
cell cycle nonspecific drugs
alkylating agents
platinum coordination complexes
antitumor abx
anti-metabolites drugs
active against S phase of cell cycle - mainly affect DNA synthesis
folate analogs
purine analogs
pyrimidine analogs
folate analog
MTX
MTX
inhibits DHFR enzyme
- inhibits purine nucleotides and deoxythymidylate nucleotide synthesis
DNA and RNA synthesis inhibited
leucovorin
activated folate - bypasses action of MTX - “provides normal tissues with reduced folate”
cells are immune to toxic effects of MTX with leucovorin. “antidote to drugs that decrease levels of folic acid to rescue BM”
if excessive amts are given, can enter tumor cells and counteract actions of MTX
MTX AE
stomatitis mucositis myelosuppression alopecia n/v
Renal damage - uncommon (complic of high dose MTX)
hepatic fibrosis and cirrhosis
pneumonitis
neurologic toxicities
Purine analogs
6-mercaptopurine
6-thioguanine
6-mercaptopurine
pro-drug
hypoxanthine analog
converted to thio-IMP via salvage pathway with HGPRT
thio-IMP inhibits first step of de novo purine synthesis (amidotransferase) - and formation of AMP and GMP (from IMP)
thio-IMP –> TGTP (can incorp self into RNA) and TdGTP (can incorporate self into DNA) = terminate synthesis
6-mercaptopurine use
ALL (childhood)
6-mercaptopurine AE
n/v/d
hepatotoxicity
BM suppresion
6-mercaptopurine metabolism
Xanthine oxidase (check if taking allopurinol)
Thiopurine methyltransferase (check for genetic deficiency)
if either are inhibited, must dec 6-MP dose to prevent AE with accumulation of drug
pt on MTX, now reports gouty like arthritis, what drug should be avoided?
allopurinol
hyperuricemia is common in anti-CA tx because of buildup of purine/pyrimidine building blocks
6-thioguanine
guanine analog
converted to TGMP by HGPRT
TGMP is able to:
- inhibit purine synthesis (PRPP amidotransferase inhibited)
- inhibits phosphorylation of GMP –> GDP (guanylate kinase enzyme inhibited)
- can convert to TGTP and dTGTP = both incorporate into RNA and DNA respectively
6-thioguanine use
nonlymphocytic leukemias
compare to 6-MP
6-thioguanine AE
n/v/d
hepatotoxicity
BM suppression
6-thioguanine metabolism
1) thiopurine methyltransferase: check for genetic deficiency
2) deamination
NO allopurinol interaction - no need to reduce 6-TG dose
DO need to reduce 6-TG dose if genetic deficiency is present
pyrimidine analogs
5-FU
capecitabine
deoxycytidine analogs: cytarabine, gemcitabine
5-fluorouracil MOA
converted to deoxyribonucleotide 5-FdUMP
5-FdUMP inhibits thymidylate synthase = DNA synthesis is inhibited
“thymineless death”
5-FU also is converted to 5’FUTP - incorporated into RNA = interfere with RNA fxn
what enzyme metabolizes 5-FU
dihydropyrimidine dehydrogenase
deficiency can result in severe toxicity = myelosuppression, neurotoxicity, life threatening diarrhea
5’fluorouracil administrated with what
leucovorin
colorectal CA tx
5-FU + leucovorin
also for solid tumors
topical for keratoses and superficial basal cell CA
5-FU AE
n/v alopecia, BM depression
“HAND FOOT SYNDROME” - erythematous desquamation of palms and soles
[eccrine sweat glands excrete 5-FU. highest concentration of eccrine sweat glands are in palms and soles - lots of 5-FU excreted here]
capecitabine
ORAL prodrug of 5-FU
activated by 3 step enzymatic conversion to 5-FU (1st two steps in liver, then in tumor cells with thymidine phosphorylase)
expression of enzyme is higher in tumor cells than normal cells
first line tx for metastatic colorectal cancer
capecitabine
also used for metastatic breast cancer
(b/c of specific activation in cancer cells)
capecitabine AE
diarrhea
hand food syndrome
myelosuppresion, n/v = incidence is a lot less than IV 5-FU
cytarabine
deoxycytidine analog
gemcitabine
deoxycytidine analog
cytarabine MOA
converted to cytarabine triphosphosphate
- competitively inhibits DNA Pol-alpha (blocks DNA synthesis)
- competively inhibtis DNA Pol-beta (blocks DNA repair)
- incorporated into DNA, RNA = interference with chain elongation and ligation of fragments
cytarabine use
hematological malignancies
NOT solid tumors
cytarabine AE
myelosuppression
mucositis
n/v
neurotoxicity
Gemcitabine
prodrug - phosphorylated to nucleoside di and tri phosphate = inhibits DNA synthesis (ribonucleotide reductase)
incorporation of gemcitabine triphosph into DNA = chain termination
Gemcitabine use
solid tumors
hematological malignancies
gemcitabine AE
flu like
n/v
myelosuppresion
renal microangiopathy syndromes
vinca alkaloids
(microtubule inhibitors)
vinblastine
vincristine
metabolized by liver P450
dose modific required in liver dysfunction
MOA: binds b-tubulin = disrupts assembly
- mitotic arrest in metaphase
AE - neurotoxicity, may disrupt functions that require microtubules
taxanes
(microtubule inhibitors)
paclitaxel
docetaxel