Oncology Need to Knows Flashcards
Define Solid Tumors
Affect organ & other solid tissues
Define Hematologic Malignancies
affect blood cells
Define primary tumor
original mass of cancer cells of a solid tumor in a body organ
Define Metastasize
spread of cancer from the primary tumor to body sites
4 modalities used in the treatment of cancer
- surgery
- radiation
- chemo
- immunomodulation (stem cell transplant, immunosuppressive or immunostimulatory agents (systemic therapies))
Explain how the principal of log cell kill kinetics is applied in the use of chemotherapy?
- a given tx kills a constant fraction of cells
- Subsequent doses reduce the cancer burden proportionally over time
- More cells killed, the higher the chance for cure.
What is the principle of cancer cell growth that describes how the growth fraction of a tumor changes over time?
Gompertzian model of tumor cell growth
Gompertzian model of tumor cell growth
- Growth fraction of a tumor is not constant
- Growth factor decreases as the tumor gets larger
- Results in decreased number of cells susceptible to chemo.
Explain why multiple chemotherapy drugs are typically combined into one treatment regimen? What other factors besides mechanism of action are considered when designing chemotherapy combinations?
- Efficacy: each drug in a regimen must has some anticancer activity when used alone
- Toxicity: Select drugs to minimize overlapping toxicities
- Optimum scheduling: each drug should be given in intervals (daily, weekly, monthly, etc) to max activity
- Mechanism of action: multiple mechanisms of action help overwhelm cells ability to develop resistance
What is dose density and how could it change while a patient is being treated with chemotherapy?
- Giving repeated doses of multiple chemotherapy agents over a period of time.
- →Chemotherapy cycles (give same drugs once every 1-4 weeks)
Neoadjuvant chemotherapy
Used prior to the use of local therapies to improve their effect by reducing the size of the tumor
Adjuvant chemotherapy
Used after local therapies to improve their long term effect
Cure
sustained cancer-free period, a prolonged period of remission (usually 5 years)
Control
- reduce cancer burden, prevent extension of cancer, and extend survival
- cure is unlikely
Palliation
- reduce symptoms of disease, improve quality of life, and prolong survival
- cure is not likely
Remission/complete response
unable to detect presence of cancer
partial response
reduction in tumor burden but cancer is still present
Treatment failure/progressive disease
cancer continues to grow despite treatment
Describe 3 possible mechanisms why chemotherapy might not work in a patient
- Mutations within cancer cells could: Block chemotherapy actions, Block uptake of chemo into cells, Facilitate excessive transport of drug back out of the cells
- Drug interactions could decrease exposure to chemo within the patient’s body: Increased metabolism of chemo agents ↓ body concentrations
- Calculated dose did not match patients individual body characteristics. Metabolic rate, distribution of the drug throughout the body to site of cancer.
What is salvage chemotherapy and when it’s used?
- Use of other combo of chemo drugs
- used when primary tx unsuccessful
Describe the difference between cell cycle specific and cell cycle nonspecific Agents
Cell cycle impact:
based on whether the agent requires to be in active phases of the cell cycle (g1, s, g2, m) or can be in resting phase (g0) as well as other phases
MOA of Cyclophosphamide
Disrupts normal DNA structure by altering atomic interactions and prevents use of DNA as a blueprint for cell division
MOA of Cisplatin
Acts similar to alkylating agents by binding DNA and forming intra- and interstrand crosslinks
MOA of MTX
-Inhibits DHFR which converts one form of folic acid to another (blocks purine synthesis)
-also inhibits TS = blocks incorporation of FUTP into RNA and dFUTP into DNA blocking formation of RNA and DNA
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MOA of Vincristine
- Inhibit tubulin polymerization required for microtubule assembly
- Prevents microtubule formation
- Microtubule inhibition blocks cell division during metaphase and causes cell death
MOA of Paclitaxel
Act by promoting microtubule formation
- prevent spindle fibers from retracting
- Preventing disassembly of microtubules blocks completion of cell division and leads to cell death
MOA of Etoposide
- Act by inhibiting DNA topoisomerase II
- Prevents proper unwinding of DNA resulting in blockade of DNA synthesis and cell division