Breast Cancer Flashcards
What are the 3 main goals,objectives of cancer treatment?
- Cure the patient (kill or remove ALL cancer cells)
- Prolong patient survival (kill MOST cancer cells)
- Palliate symptoms (kill SOME cancer cells)
What is chemotherapy in a clinical context?
Drugs that target cancer cells.
When is chemotherapy used?
- For patients with advanced disease where no other treatment exists.
- Adjuvant chemotherapy: systemic treatment following local radiotherapy or surgery to control microscopic metastasis.
- Primary or Neo-adjuvant chemotherapy: as initial therapy for locally advanced cancer to render it more amenable to subsequent surgery.
Why might patients relapse after apparently being cured?
Microscopic metastasis or resistant cells.
What does chemotherapy target and why is this a disadvantage?
Targets cell replications in cancer cells AND normal cells, which can kill healthy cells.
What is the resting phase of the cell cycle?
G0.
In which phase is DNA replicated?
S.
What is the pre-mitotic phase of the cell cycle?
G2.
What is mitosis in the cell cycle?
M.
What are cell cycle specific drugs and give examples?
They target cell cycle points.
Examples:
- S phase: antimetabolites, topoisomerase inhibitors.
- G0 phase: micro-tubule inhibitors, topoisomerase inhibitors, alkylating agents.
What assumptions do we make about chemotherapy?
- Heterogeneous nature.
- Dosage response is different.
- Humans are starting to become intolerant to chemotherapy.
- Different drugs have different kill properties.
What is the log-kill kinetics model?
It states that every dose of chemotherapy kills cells by a certain proportion, and cancer cells can grow between cycles.
Describe tumor kinetics (Gompertzian growth curve).
- Initial slow phase.
- Exponential growth.
- Plateau phase as they exhaust nutrients, oxygen, and blood supply.
Why is adjuvant chemotherapy effective?
It targets rapidly growing cancer cells in the initial slow phase.
When is clinical detection usually made, and what is the consequence?
In the phase 3 plateau phase, where the cancer is no longer growing quickly.
What is the principle of dose intensity (Norton-Simon hypothesis)?
Giving less time between doses.
What limits us from using the dose intensity hypothesis?
We need to allow our normal cells, especially bone marrow cells, to recover.
How are chemotherapy agents classified?
Based on mechanism of action.
What are the types of chemotherapy agents?
- Alkylating agents.
- Platinum agents.
- Antimetabolites.
- Topoisomerase inhibitors.
- Anti-microtubular agents.
- Other agents.
- Molecular targeted agents.
What is the mechanism of alkylating agents?
They form covalent adducts, transferring alkyl groups to DNA bases, resulting in single or double strand breaks.
What is the specificity of alkylating agents?
Limited cell cycle specificity as they bind directly to DNA.
What are the types of alkylated adducts?
They inhibit cell replication.
What is the mechanism of platinum agents?
They bind covalently to purine DNA bases, resulting in bifunctional intrastrand cross-links that prevent DNA double strands from separating.
What is the specificity of platinum agents?
Not S phase specific.
