Cancer II Flashcards
What do most chemotherapeutic agents interfere with? Which cells are more sensitive to chemo?
Cell proliferation and/or induce apoptosis;
rapidly dividing cancer cells more so than normal cells
What is the log-kill hypothesis? What is the relationship between cell viability and drug concentration?
Given dose of drug kills CONSTANT FRACTION of cells rather than CONSTANT NUMBER of cells (first order); cell via decreases with increased drug concentration
What are the principles of combination therapy?
- Drugs should have individual anticancer actions
- Drugs ought to act by different mech’s
- Ideally have synergistic or additive effects
- Consider different dose-limiting toxicities
- Give several cycles of treatment
What are advantages of chemo?
- Provide max cell killing with less toxicity
- Effective against HETEROGENEOUS pop’s present in tumors
- Reduce chance of development of resistant clones
Limitations of chemo?
A. Drug resistance in long term (decreased cell uptake, abnormal transport of drug, increased cellular inactivation, altered target protein, reduced affinity for drug, enhanced repair of DNA damage)
B. Toxicity (neutropenia, thrombocytopenia, anemia, nausea/vomiting, stomatitis, alopecia (hair loss), leukemia/myelodysplasia
Regarding their actions on the cell cycle, how can anti-cancer drugs be divided?
- Cell cycle-specific drugs (active in specific phase of cell cycle)
- Cell cycle-nonspecific drugs that kill both cycling and noncycling tumor cells
For metchlorethamine, and other drugs!! List class, mech, therapeutics, important side effects, other side effects, and miscellaneous
Class: Nitrogen mustard
Mech: alkylating agent that has spontaneous conversion to active metabolites in body fluids or enzymatically converted in liver
Thera: Hodgkin’s; used topically for treatment of cutaneous T-cell lymphoma
Important SE’s: none
Other SE’s: severe nausea, vomiting, myelosuppression (leukopenia, thrombocytopenia)
Miscellaneous: not used much anymore due to sterility
For cyclophosphamide, list:
Class: Nitrogen mustard
Mech: alkylating agent; conversion hepatic cytochrome P450 to active metabolite phosphoramide mustard
Thera: Most widely used alkylating agent; singly or in combo for ALL, CLL, non-Hodgkin’s, breast, lung and ovarian cancer
Important SE: Hemorrhagic cystitis (toxic metabolite acrolein accumulates) but hydrating and using MESNA can minimize problem
Other SE’s: Nausea, vomiting, myelosuppression
Miscellaneous: relatively long plasma half-life (7-15 hours) and taken ORALLY!!
What is the only difference between ifosfamide (Ifex) and cyclophosphamide?
Sarcoma and testicular cancer for therapeutics
Carmustine (Gliadel) list
Class: nitrosourea
Mech: Alkylating agent
Therapeutics: brain tumors (cross BBB)
Important SE’s: renal toxicity, pulmonary fibrosis
Other SE’s: profound myelosuppression, severe nausea and vomiting
Lomustine (Ceenu) list
Class: nitrosourea
Mech: Alkylating agent
Therapeutics: brain tumors (cross BBB)
Important SE’s: renal toxicity, pulmonary fibrosis
Other SE’s: profound myelosuppression, severe nausea and vomiting
Decarbazine (DTIC)
Class: Triazene
Mech: Alkylating agent; prodrug activated by liver cytochromes
Thera: part of ABVD for Hodgkin’s, also malignant melanoma
Other side effects: Nausea and vomiting, myelosuppression (neutropenia, thrombocytopenia), flu-like symptoms (fever, fatigue)
Miscellaneous: IV admin
Temozolomide
Class: Triazene Mech: Alkylating agent, nonenzymatic conversion to methylhydrazine in physiologic pH Thera: Malignant gliomas Important side effects: None Other side effects: same as DTIC Miscellaneous: take orally
Cisplatin (Platinol)
Class: Platinum analogs
Mech: Alkylating agents that do not form carbonium ion intermediates or formally alkylate DNA; covalently bind nucleophilic sites on DNA (e.g., guanine N7); converted to active cytotoxic forms by reacting with water to form (+)charged, hydrated intermediates that react with DNA guanine, forming inter- and intrastand cross-links
Thera: Testicular, ovarian, cervical, and bladder cancers; also useful in treatment of head and neck cancer, and lung carcinoma
Important SE’s: Nephrotoxicity, ototoxicity, peripheral motor and sensory neuropathy at high doses
Other SE’s: Severe nausea and vomiting, mild to moderate myelosuppression
How is carboplatin (paraplatin) different from cisplatin?
Thera: Ovarian cancer
Important side effects: None
Other side effects: just myelosuppression