- Also called:
- antineoplastic drug
- Key People:
- George Herbert Hitchings
- Gertrude B. Elion
- Related Topics:
- etoposide
- Herceptin
- sipuleucel-T
- vincristine
- busulfan
anticancer drug
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What is an anticancer drug?
An anticancer drug is any medication effective in treating malignant, or cancerous, diseases. The term chemotherapy is often equated with the use of anticancer drugs; however, it more accurately refers to using chemical compounds to treat disease generally.
There are several major classes of anticancer drugs, including:
* Alkylating agents
* Antimetabolites
* Natural products
* HormonesSince the late 20th century, molecular features unique to cancer cells have spurred targeted cancer therapies with relatively high specificity for cancer cells. Because cancer cells are similar to normal human cells, anticancer agents are generally toxic to normal cells and can cause numerous side effects.
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How do anticancer drugs work in the body?
Anticancer drugs combat malignant diseases using various methods, such as alkylating agents, antimetabolites, natural products, and hormones.
Alkylating agents modify cancer cell DNA to prevent replication, while antimetabolites disrupt cell metabolism by interfering with DNA or RNA production. Natural products like paclitaxel and vinca alkaloids, derived from plants, halt cell division. Hormones antagonize growth-stimulating hormones in hormone-sensitive cancers like breast and sex organ cancers.
These drugs target rapidly dividing cells, including cancer cells. However, they can also harm normal cells, leading to side effects like hair loss, nausea, and bone marrow toxicity. Targeted therapies, like monoclonal antibodies and small-molecule drugs, offer more specific action against cancer cells, reducing harm to normal cells.
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What are some common types of anticancer drugs?
Anticancer drugs are used to treat malignant diseases, with major classes including alkylating agents, antimetabolites, natural products, and hormones.
Alkylating agents like nitrogen mustards and cisplatin change the DNA and RNA of cells, preventing replication, and are used for lymphoma, leukemia, and other cancers.
Antimetabolites interfere with normal cell metabolism by competing with a cell's metabolites. Examples include mercaptopurine and fluorouracil.
Hormones, such as tamoxifen, antagonize the hormones that certain cancers need to grow, and are mainly used for breast and sex organ cancers.
Targeted therapies, including monoclonal antibodies and small-molecule drugs, can neutralize molecules responsible for tumor cell behavior.
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How do anticancer drugs target cancer cells but affect healthy cells too?
Anticancer drugs target rapidly dividing cancer cells, but they often affect healthy cells because they can't always distinguish between the two. These drugs work by interfering with cell growth and division, which impacts both cancerous and normal cells.
Since cancer cells proliferate faster than most healthy cells, anticancer drugs disproportionately affect them. However, normal cells that also divide rapidly, such as those in hair follicles, the mouth, and bone marrow, are also vulnerable to these drugs. This can result in side effects like hair loss, mouth sores, and reduced resistance to infection.
Targeted therapies are a newer approach that aims to be more specific by attacking molecules responsible for specific tumor cell behavior, resulting in less toxicity to normal cells compared to traditional chemotherapeutic agents.
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What are some common side effects of anticancer drugs?
Anticancer drugs, essential for treating malignancies, can cause various side effects due to their impact on both cancer and healthy cells. Common side effects include:
- Hair loss
- Mouth sores
- Cardiac anomalies
- Bone marrow toxicity
- Nausea and vomiting
- Anemia
- Reduced resistance to infection
- Increased bleeding
- Infertility
Targeted therapies may cause skin rashes, diarrhea, fatigue, headaches, muscle aches, and high blood pressure. More severe conditions include cardiotoxicity, bleeding, and lung inflammation. The severity and type of side effects can vary based on the drug, dosage, and individual patient factors.
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How do doctors decide which anticancer drug to use for a patient?
The decision to use a certain anticancer drug depends on the type and location of the cancer, its severity, and whether surgery or radiation therapy can or should be used. The side effects associated with the drug are also a factor.
Greater insight into the causes and mechanisms of cancer has led to better ways to diagnose and treat the many forms of this disease. Demonstration of specific mutations in tumors is a crucial part of deciding which drugs to use for a given patient. Molecular evaluation advanced significantly in the early 21st century, following the publication in 2003 of the first complete full-length sequence of the human genome. The identification of specific genetic alterations allows physicians to select from an expanding group of drugs that have been specifically developed to interfere with the abnormal functions associated with tumor mutations.
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anticancer drug, any drug that is effective in the treatment of malignant, or cancerous, disease. Anticancer drugs are grouped according to how they work against cancer cells. Some, such as alkylating agents, antimetabolites, antitumor antibiotics, and topoisomerase inhibitors, directly disrupt cell division or damage DNA. Others—such as hormone therapies, targeted therapies, and immunotherapies—act more precisely, blocking specific growth signals or helping the immune system attack cancer. Broadly, these medicines fall into two categories: cytotoxic drugs, which destroy rapidly dividing cells, and non-cytotoxic drugs, which interfere with the molecular pathways or environments that allow cancer to thrive.
The first anticancer agents
The term chemotherapy frequently is equated with the use of anticancer drugs, although it more accurately refers to the use of chemical compounds to treat disease generally. One of the first chemotherapeutic drugs used clinically in modern medicine for the treatment of cancer was the alkylating agent mechlorethamine, a nitrogen mustard that in the 1940s was found to be effective in treating lymphomas. In 1956 the antimetabolite methotrexate became the first drug to cure a solid tumor, and the following year 5-fluorouracil was introduced as the first of a new class of tumor-fighting compounds known as pyrimidine analogs. Since then many anticancer drugs have been developed and used with much success.
Clinical considerations
- Alkylating agents: Cause damage to DNA to prevent cancer cells from reproducing. Examples include cyclophosphamide, cisplatin, carboplatin
- Antimetabolites: Mimic normal cellular molecules, disrupting DNA and RNA synthesis. Examples include methotrexate, 5-fluorouracil (5-FU), cytarabine, and gemcitabine.
- Antitumor antibiotics: Interfere with DNA replication and repair by binding directly to DNA. Examples include doxorubicin, daunorubicin, and bleomycin.
- Mitotic inhibitors: Block cell division via disruption of microtubule function. Examples include vincristine, vinblastine, paclitaxel, and docetaxel.
- Targeted therapies: Act on specific molecular targets involved in tumor growth and survival. Examples include imatinib (Gleevec), trastuzumab (Herceptin), rituximab, and erlotinib.
- Immunotherapies: Stimulate or restore immune function, enabling it to fight cancer. Examples include immune checkpoint inhibitors (nivolumab, pembrolizumab), chimeric antigen receptor T-cell therapy (CAR-T therapy), and cytokines.
The decision to use a certain anticancer drug depends on many factors, including the type and location of the cancer, its severity, whether surgery or radiation therapy can or should be used, and the side effects associated with the drug. Most anticancer drugs are administered intravenously; however, some can be taken orally, and others can be injected intramuscularly or intrathecally (within the spinal cord).
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The treatment of cancer is complicated in that the drugs used target human cells, albeit cells that have undergone genetic changes and are dividing at a fast and uncontrolled rate. However, certain anticancer drugs can differentiate to some degree between normal tissue cells and cancer cells, and the rate at which cancer cells proliferate may in fact play a role in the apparent selectivity of agents. For instance, alkylating agents, which act on cells at all stages of the cell cycle, appear to be most toxic to cells in the synthesis, or S, stage, when DNA is in the process of replicating and unpaired nucleotides (the nitrogen-containing units of DNA and RNA) are most vulnerable to alkylation (the addition of an alkyl group). In the late 20th and early 21st centuries, the identification of molecular features unique to cancer cells fueled the development of targeted cancer therapies, which possess a relatively high degree of specificity for cancer cells.
Side effects
The specificity of anticancer drugs plays an important role in reducing the severity of side effects associated with the drugs’ use. Indeed, because cancer cells are similar to normal human cells, anticancer agents are generally toxic to normal cells and can cause numerous side effects, some of which are life-threatening. Such side effects include hair loss, sores in the mouth and on other mucous membranes, cardiac anomalies, bone marrow toxicity, and severe nausea and vomiting. The bone marrow toxicities result in anemia as well as in decreased resistance to infectious agents. Permanent infertility can also result. Those adverse effects may require that the drug dosage be reduced or the drug regimen be changed to make the drug tolerable to the patient.
In rare instances prolonged use of anticancer drugs can lead to the development of secondary cancers. The type of agent, the primary cancer that it is used to treat, and the total cumulative dose administered influence the extent to which an anticancer drug is carcinogenic (cancer-causing). Frequently occurring secondary cancers associated with anticancer drug therapy are myelodysplastic syndrome and acute leukemias, risk of which is increased particularly with the use of alkylating agents and topoisomerase inhibitors (e.g., etoposide).
The side effects associated with anticancer drugs can be reduced through the use of multiple agents, which often enables the administration of lower dosages of each drug. The use of multiple agents may also reduce the incidence of cellular resistance, a phenomenon that allows tumours to escape treatment and to continue to grow after a period of remission (absence of disease activity). Multidrug therapy is based on the premise that different types of anticancer drugs exert their effects in a certain part of the cell cycle (e.g., cell growth phase, cell division phase, resting phase). Thus, one drug may be used to stop the growth of cancer cells in a certain phase, while another agent may work at a different phase. In addition to using complex regimens that employ several drugs, cancer chemotherapy is often combined with surgery to reduce the number of cancer cells and with radiation treatment to destroy more cells.
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