Although the term is usually used generally as simply chemo, there are several different types of chemotherapy that are commonly used to combat cancer. People receiving, or who know someone who will receive, chemotherapy may ask what is chemotherapy and what chemotherapy types are available.

Chemotherapy is the word used to describe any disease, usually cancer, treatment that involves chemicals. This is nearly always applied to cancerous tumors that have begun to spread throughout the body. Different types of chemotherapy have been developed to combat tumors at various stages and sizes. These chemicals inhibit the division of cancerous cells, hopefully stopping the spread of and possibly even killing the tumor.

The different types of chemotherapy drugs are classified into groups, similar to most common prescriptions. Each category encompasses several different drugs which can be used alone or in combination with other chemotherapy types. Because of the way the drugs affect the body, all types of chemotherapy carry risks for long term side effects.

Antitumor antibiotics are similar in origin to penicillin or other mold based prescriptions. These drugs are derived from fungi, and prevent the DNA of the tumor from being replicated. When the DNA cannot replicate, the tumor cannot grow. Anti tumor antibiotics carry a risk of heart damage or treatment induced leukemia, due to their interference in DNA replication.

Plant alkaloids are a class of drugs that are derived from specific plants. This type of chemotherapy involves attacking the cell at specific phases in its development to prevent reproduction. Several different plants are used to manufacture these drugs, including the Pacific Yew and Asian Happy Tree.

Alkylating agents are the oldest form of modern chemotherapy. These drugs attack the cell while at rest by damaging its DNA. With damaged DNA, the tumor is unable to reproduce and the cancer stops spreading. However, similar to antitumor antibiotics, alkylating agents bring a risk of treatment induced leukemia. This type of chemotherapy is most effective for treating slow growing cancers.

Antimetabolites are drugs that pose as substances that DNA uses to reproduce. The cancerous cells then ingest these drugs. Antimetabolites affects the cell so it is incapable of reproducing, and, because it has been posing as nutrients, starves the cell to death.

Mitotic inhibitors are designed to prevent mitosis, or cell division. They also act to prevent the materials necessary for reproduction from reaching the cell. These drugs are most effective during the cells’ reproductive cycle, but can damage a cell at any time. Nerve damage is the most common, serious side effect.

Topoisomerase inhibitors act upon cells similarly to antitumor antibiotics by inhibiting the DNA from replicating. By blocking the topoisomerase enzyme, the drug effectively cripples the cell’s DNA so it cannot be replicated. Topoisomerase inhibitors also raise the risk of treatment induced leukemia.

There are several drugs that were no developed for cancer treatment, but have since been discovered to yield positive outcomes. Corticosteroids, such as prednisone, are used to attack and kill cancer cells, as well as to relieve the symptoms of other chemotherapy treatments. Hormone inhibitors are used to treat hormone related cancers, such as breast cancer.

As scientists learn more about cancer, more inventive and targeted drugs are researched and tested. Some drugs may force a young cancer cell to mature into a healthy cell, while other may directly attack cancerous cells due to a specific mutation.