Chemotherapy Flashcards
Multi-modal treatments
surgery, radiation, chemotherapy
Rationale for anti-neoplastic drugs
- kill all tumor cells
- suppress the growth of tumor but not normal cells
- increase host capacity to fight cancer
Ideal Ant-Neoplastic Drug
- non-toxic to normal cells
- kill all tumor cells
- broad spectrum of activity
- good distribution in body (adequate half-life)
- non-immunogenic
- low incidence of side effects
- low cost, oral dosing
Currently available chemotherapy
- Poor selective toxicity
- Most drugs only affect actively growing cells
- Have limited anti-tumor spectrum
- high incidence of side effects
- Cause secondary malignancy (after treatment of cancer time then develop second cancer)
Risk of Anti-Neoplastic drugs causing secondary malignancy
high risk: mechlorethamine, carmustine, topside
low risk: doxorubicin, cyclophosphamide,procarbazine, cisplatin
low risk: vincristine, vinblastine, methotrexate, cyarabine, 5-FC
unknown: paclitaxel, bleomycin
General ways to stop tumor growth
Cell death- cell killing compound
- direct kill (necrosis)
- trigger apoptosis
Stop Growth-cytostatic compound
- induce terminal differentiation
- interfere with growth signals
Mechlorethamine, Carmustine
Cell-cycle nonspecific
Alyklyating agent
Cyclophosphamide
Cell-cycle specific/ Phase non-specific
Alkylating Agent
Mechanism: introduce alkyl groups into DNA and cross links and cause strand break by forming aziridine ring (unstable)
Side effects: hematopoiesis suppression, GI effects through intestinal mcusoa, nausea and vomiting, alopecia
Alkylating agent
Mechlorethamine, Carmustine, Cyclophosphamide
Mechlorethamine
Alkylating Agent
MOA: bi functional alkylating agent that produces DNA cross-link
Combination therapy for Hodgkin’s and nOn-hodgkin’
Highly reactive so disappear in blood in seconds to minutes
Cyclophosphamide
Alkylating Agent
Prodrug activated by liver cytochrome P450s
Mechanism: The phosphoramide mustard acts as an alkylating agent
Bladder toxicity: sterile hemorrhagic cystitis (prevent with mesna)
Broad spectrum activity against wide variety of cancers (most widely used agent in this class)
Hodgkin’s and non-Hodgkin’s, multiple myeloma, neuroblastoma, leukemia
carcinoma of endometrium, breast, lung
Carmustine (BCNU)
Alkylating Agent
Cross the blood-brain barrier–> lipophilic
Uses: brain tumors, multiple myeloma, melanoma
Toxicity: similar to other alkylating agents
cycle-nonspecific
Methotrexate
Anti Metabolite Class (Folate Analog)
Mechanism: bind to dihydrogolate reductase (DHFR) and prevent formation of tetrahydrofolate (block FH2–>FH4) needed for thymidine synthesis
Side effects; intestinal epithelium damage, bone marrow suppression, renal tubular necrosis, displace other drugs from serum albumin, hepatotoxicity
Indications: acute lymphocytic leukemia, Choriocarcinoma (can cure)
Leucovorin Rescue
High doses methotrexate bind all dihydrofolate reductase (DHFR) and inhibits all activity
Follow by rescue with leucovorin
It is a folinic acid, a fully reduced floated that does not require reduction by DHFR
normal cells have increased capacity to bring in leucovorin relative to normal cells
Fluorouracil (5-FU)
Antimetabolite (Pyrimidine Analog)
Mechanism: pyrimidine analog that is activated in cells to FUTP which inhibits RNA synthesis and to Fdump which interferes with thymidylate synthase and ultimately DNA synthesis
S-Phase specific
Side effects; nausea, anorexia, diarrhea, myelosuppression
Broad spectrum uses: carcinoma of stomach, colon, pancreas, ovary, head and neck, breast, bladder and topical for basal cell carcinoma