Chemotherapy

Types

Chemotherapy may be used alone or combined with surgery, radiation or other approaches to cancer treatment. Chemotherapy may be used in different setting with different goals, including the following:

Goals of Chemotherapy

Adjuvant — Chemotherapy administered after surgery or other primary therapy, typically given when there are no visible signs of the cancer being present, intended to lessen the risk of cancer recurrence and improve the chance of a cure.
Neo-adjuvant — Chemotherapy administered before the primary cancer therapy (usually surgery), intended to render the cancer more easily removable during surgery and to lessen the risk of cancer recurrence after surgery.
Radiosensitizing — Chemotherapy given in conjunction with radiation therapy, intended to boost the anticancer effects of radiation therapy.
Curative intent — Chemotherapy administered with the intent to cure the cancer.
Palliative — Chemotherapy given in the setting of no known available curative therapies, intended to lessen a patient's cancer symptoms and with the hope of extending life.

Types of Chemotherapy Drugs

Drugs that generally kill cancer cells are referred to as cytotoxic agents. Common types of cytotoxic chemotherapy drugs include:

Alkylating agents modify/damage cancer cell DNA and block the replication of DNA, therefore interfering with the growth of cancer cells.
Antimetabolites block the enzyme pathways needed by cancer cells to live and grow.
Antitumor antibiotics block certain enzyme and cancer cell changes, thus affecting DNA.
Mitotic inhibitors slow cancer cell division or hinder certain enzymes necessary in the cell reproduction process.
Nitrosoureas impede enzymes that repair DNA.

Other Chemotherapy Drugs

Other drugs used in cancer therapy include:

Hormonal agents target the hormonal processes that may stimulate cancer cell growth and/or survival.
Biological agents affect natural processes that may stimulate cancer cell growth and survival.
Immunotherapy is intended to boost the recognition of cancer cells by the body's immune system, thereby helping the body to kill cancer cells.
Cellular therapy involves the use of immunologic cells that selectively destroy cancer cells.
Signal transduction inhibitors are given to disrupt abnormal processes present within cancer cells and are necessary for the growth or survival of cancer cells.
Radiopharmaceuticals are substances that have been marked with radioactive markers to selectively deliver radiation therapy to cancer cells.
Anticancer antibodies are specially engineered antibodies given with the goal of selectively targeting cancer cells for removal by the immune system.
Anticancer vaccines contain agents intended to help the immune system more readily recognize cancer cells as foreign (and thus attack them).
Anticancer viral therapies involve giving viruses to patients with the hope that the virus will selectively kill cancer cells. (This treatment is currently highly experimental.)
Gene therapies introduce DNA/genetic material into cancer cells in hopes of either restoring them to normal or killing them. (This treatment is currently highly experimental.)