Chemotherapy is the use of anti-cancer (cytotoxic) drugs to treat cancer. Either one chemotherapy drug or a combination of different drugs is used during treatment.
Chemotherapy is used either in isolation as a treatment option itself or is often paired with surgery, radiotherapy and immunotherapy or a combination of these. Currently there are more than 100 types of chemotherapy drugs and new ones are being developed all the time.
Types of Chemotherapy
Chemotherapy drugs can be grouped by how they work their chemical structure and their relationship to other drugs. Some drugs work in more than one way, and may belong to more than one group. (Note: not all chemotherapy drugs are listed here)
Alkylating agents: These drugs keep the cell from reproducing by damaging its DNA. They work in all phases of the cell cycle. They are used to treat many different cancers, including lung, breast and ovary as well as leukemia, lymphoma, Hodgkin disease, multiple myeloma and sarcoma. As these drugs damage DNA, they can affect cells of the bone marrow which make new blood cells; hence in rare cases this can lead to leukaemia,
Examples of alkylating agents include: Altretamine, Busulfan, Carboplatin, Carmustine, Chlorambucil, Cisplatin, Cyclophosphamide, Dacarbazine, Lomustine, Melphalan, Oxaliplatin, Temozolomide, Thiotepa, etc.
Antimetabolites: These drugs interfere with DNA and RNA growth by substituting for the normal building blocks of RNA and DNA. They damage cells during the phase when the cell’s chromosomes and bring copied. They are commonly used to treat leukemias, breast cancer, ovarian cancer, intestinal tract cancer, as well as other types of cancers.
Examples of antimetabolites include: 5-fluorouracil (5-FU), 6-mercaptopurine (6-MP) Capecitabine (Xeloda), Cytarabine (Ara-C), Floxuridine, Fludarabine, Gemcitabine (Gemzar), Hydroxyurea, Methotrexate, Pemetrexed (Alimta), etc.
Anti-Tumour antibiotics: These drugs are not like the antibiotic used to treat infections. They work by changing the DNA inside the cancer cells to keep them from growing and multiplying. These Durgs are either Anthracyclines or not.
- Anthracyclines: These are anti-tumor antibiotics that interfere with enzymes involved in copying DNA during the cell cycle. (Enzymes are proteins that start, help or speed up the rate of chemical reactions in cells). They are widely used for a variety of cancers. A major concern when giving these drugs is that they can permanently damage the heart, if given in high doses. For this reason, lifetime dose limits are often placed on these drugs.
Examples of anthracyclines include: Daunorubicin, Doxorubicin (Adriamycin), Epirubicin, Idarubicin, etc.
- Anti-tumor antibiotics that are not anthracyclines include: Actinomycin-D, Bleomycin, Mitomycin-C, Mitoxantrone (also acts as a topoisomerase II inhibitor), etc
Topoisomerase inhibitors: These drugs interfere with enzymes called as topoisomerase, which help separate the strands of DNA so they can be copied. (enzymes are proteins that cause chemical reactions in living cells). These drugs are used to treat certain leukemias, as well as lung ovarian, gastrointestinal and other cancers.
Topoisomerase inhibitors are grouped according to which type of enzyme they affect:
- Topoisomerase I inhibitors: These include topotecan, Irinotecan (CPT-11)
- Topoisomerase II inhibitors: These include Etoposide (VP-16), Teniposide, Mitoxantrone (also acts as an anti-tumour antibiotic). These can increase the rick of a second cancer – acute myelogenous leukemia (AML) – as early as 2-3 yers after the drug is given.
Mitotic inhibitors: These are compounds derived from natural products, such as plants. They work by stopping cells from dividing to form new cells but can damage cells in all phases by keeping enzymes from making protein needed for cell production. They are used to treat many different types of cancers including breast, lung, myelomas, lymphomas and leukemias. These drugs may cause nerve damage, which can limit the amount that can be given.
Examples of mitotic inhibitors include: Docetaxel, Estramustine, Ixabepilone, Paclitaxel,Vinblastine, Vincristine, Vinorelbine, etc
Corticosteroids: These are often simply called steroids. They are natural hormones and hormone – like drugs that are useful in the treatment of many types of cancer, as well as other illnesses. When these drugs are used as part of cancer treatment, they are considered as chemotherapy drugs. They are commonly used to help prevent nausea and vomiting caused by chemotherapy. They may be used before chemotherapy to help prevent severe allergic reactions.
Examples of corticosteroids include: Prednisone, Methlyprednisolone )Solumedrol), Dexamethasone (Decadron), etc.
Other Chemotherapy Drugs: Some chemotherapy drugs act in slightly different ways and do not fit well onto any other category.
Examples include: Drugs like L-asparaginase; which is an enzyme and proteasome inhibitor bortezomib (Velcade).
Targeted therapies: These drugs attack cancer cells more specifically than traditional chemotherapy drugs. These drugs can be used a part of the main treatment, or they may be used after treatment to keep the cancer under control or keep it from coming back.
Examples include: Olaparib, Niraparib, Rucaprib
Differentiating agents: These drugs act on cancer cells to make them mature into normal cells.
Examples include: retinoids, tretinoin (ATRA or Atalin), bexarotene (Targretin) as well as arsenic trioxide (Arsenox).
Hormone therapy: Drugs in this category are sex hormones, or hormone-like drugs, that are used to slow the growth of breast, prostate and endometrial (uterine) cancers, which normally grow in response to natural sex hormones in the body. They work by making the cancer cells unable to use the hormone they need to grow, or by preventing the body from making the hormone.
Immunotherapy: Some treatments are given to people with cancer to help their immune system recognise and attack cancer cells.
COMPARE PRICING FOR - Chemotherapy
Side effects vary from person to person and usually get better or go away once chemotherapy has finished. The common side effects of chemotherapy are:
- Mouth ulcers or sores
- Nausea & vomiting
- Hair loss
- Anaemia (low red blood cell counts)
- Fatigue, tiredness and weakness
- Drop in platelet count, hence easy bruising or bleeding
- Increased risk of getting infections
- It may damage the nerves in the hands and feet, causing tingling and numbness
- Mouth, tongue and throat problems such as sores and pain with swallowing
- Skin, urine and bladder changes with kidney problems
- Nail changes such as dry skin and colour changes
- Weight changes
- Reduced appetite
- Constipation and diarrhoea
- Changes in mood, causing low mood
- Chemo brain which can affect concentration and focus
- Changes in libido and sexual function
- Fertility problems