Chemotherapy
Definition: Chemotherapy is a cancer treatment that uses specific drugs (cytotoxic agents) to kill fast-growing cells in the body, primarily cancer cells. Because cancer cells typically divide and multiply much faster than most normal cells, chemotherapy is effective by targeting the cell division process.
Mechanism of Action: Chemotherapy drugs work in various ways to damage the control center (the DNA) or interfere with the machinery of a dividing cell:
DNA Damage: Many agents (like alkylating agents) directly damage the DNA strands within the cell nucleus, preventing the cell from replicating or repairing itself.
Interference with Replication: Other agents (like antimetabolites) mimic the normal building blocks of DNA and RNA, causing errors when the cell attempts to construct new genetic material.
Microtubule Inhibition: Some drugs (like taxanes or vinca alkaloids) interfere with the tiny structures (microtubules) essential for separating chromosomes when the cell divides.
Administration and Uses:
Administration: Most commonly given intravenously (IV), but can also be taken as pills, injections, or applied directly to a specific body cavity (e.g., intraperitoneal).
Purposes:
Cure: To eliminate the cancer entirely.
Control: To shrink tumors and stop the spread of cancer.
Palliative: To relieve symptoms and improve quality of life.
Neoadjuvant: Given before surgery or radiation to shrink a tumor.
Adjuvant: Given after surgery or radiation to kill any residual cells and prevent recurrence.