Chemotherapies

Chemotherapy is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents) as part of a standardized chemotherapy regimen. Chemotherapy may be given with a curative intent (which almost always involves combinations of drugs), or it may aim to prolong life or to reduce symptoms (palliative chemotherapy).

Chemotherapy works by killing cells that divide rapidly, a common characteristic of cancer cells. However, it can also affect rapidly dividing cells of normal tissues, such as those in the hair follicles, bone marrow, and the digestive tract, leading to the side effects of treatment.

Types of Chemotherapy

Chemotherapy drugs can be classified in various ways, including by their chemical composition, mechanism of action, and their relationship to another drug with the same mechanism. Some major categories include alkylating agents, antimetabolites, anti-tumor antibiotics, topoisomerase inhibitors, and mitotic inhibitors.

Alkylating Agents

Alkylating agents are the oldest group of chemotherapeutics and work by directly damaging DNA to prevent the cancer cell from reproducing. Because these agents affect both cancerous and normal cells, patients are at risk for side effects.

Antimetabolites

Antimetabolites interfere with DNA and RNA growth by substituting for the normal building blocks of RNA and DNA. These agents are similar in structure to the normal building blocks but differ enough to interfere with DNA synthesis, affecting cancer cell growth.

Anti-tumor Antibiotics

Anti-tumor antibiotics have a dual role; they interfere with the DNA of cancer cells and have an antibiotic effect that can help fight infections. However, unlike traditional antibiotics, they're not used to treat infections.

Topoisomerase Inhibitors

Topoisomerase inhibitors work by interfering with the enzyme topoisomerase, which helps separate the strands of DNA so they can be copied. By interfering with this process, these drugs can prevent cancer cells from dividing.

Mitotic Inhibitors

Mitotic inhibitors inhibit the process of mitosis in cell division. They are derived from natural products such as plants and prevent cancer cells from dividing to form new cells.

Administration

Chemotherapy can be administered through various routes, including intravenous (IV), oral, intramuscular (IM), topical, and more. The method of administration often depends on the specific drug and the type of cancer being treated.

Side Effects

The side effects of chemotherapy can vary widely and depend on the type of drug, the dosage, and the individual patient. Common side effects include nausea and vomiting, hair loss, fatigue, increased risk of infection, and more. Many side effects can be managed or mitigated through supportive care and medications.

Future Directions

Research in chemotherapy continues to evolve, with efforts focused on finding more effective, less toxic drugs, as well as methods to specifically target cancer cells to minimize damage to normal cells. This includes the development of targeted therapy and immunotherapy, which aim to more precisely target cancer cells while sparing healthy ones.