Chemotherapy is one of the medical treatment methods used by doctors to treat various types of cancer. This treatment is considered to be more efficient at destroying cancer cells that have spread and affected many areas of the body. This is because the chemo drugs spread across the whole body and destroy any rapidly multiplying cancer cells.
How are Chemotherapy Treatments Classified?
There are various types of chemotherapy. The different types of chemotherapies are differentiated based on the type of drugs used for the chemotherapy treatment. There are drugs that can be found in more than one class of chemo drugs while others are in a specific category.
Types of Chemo Drugs Based on the Cell Cycle
One of the main methods of classifying chemo drugs is through the cell cycle. The cell cycle simply outlines the various stages and processes that cancer cells undergo as they create new cells.
As far as the cell cycle is considered, there are chemotherapy drugs that work best when the cells are actively dividing while other drugs are better at destroying cancer cells at specific stages of the cell cycle. Some drugs even affect cancer cells while they are in their resting stage.
There are certain drugs that are most effective when the cancer cells are actively dividing but the cells do not have to be in a specific phase for it to work. These drugs are classified as phase nonspecific drugs.
Phase specific drugs are those that are most effective when the cancer cells are in a given phase of the cell cycle.
Other Categories of Chemotherapy Drugs
1. Alkylating Agents
These drugs work by damaging the DNA of the cancer cells. Therefore they interfere with the replication of the DNA and prevent it from being copied. Since cancer cells multiply very quickly, they will not have the time to correct the changes caused to their DNA.
Examples of some type of drugs that fall into this category are:
- Busulfan which is an Alkylsulfonate.
- Cisplatin and Carboplatin which are metal salts
- Hexamethylmelamine which falls under Ethylenimines
- Dacarbazine, Temozolomide and Altretamine which are Hydrazines
- Nitrosureas such as lomustine. Nitrosureas are excellent in treating cancers of the brain as they are able to cross the barrier between blood and the brain.
Just as the name suggests, these drugs work by posing as substitutes in the normal metabolic processes in a human being. They replace normal metabolites and affect the tumor cells. These drugs affect the cancer cells more than they affect the normal cells.
Examples of such drugs are Methotrexate, Foxuridine, Capecitabine, Fludarabine, Pentostatin and 5-Fluoroouracil.
3. Antitumor Antibiotics
These are manufactured from natural materials made by a type of soil fungi known as Streptomyces. They also prevent the cancer cells from reproducing. Examples of such drugs are,
- Idarubicin and Doxorubicin which are under the category of Anthracycines
- Plicamycin which is under Chromomycins.
4. Plant Alkaloids
These are drugs manufactured from plants. They destroy cancer cells at all phases of the cell cycle. Examples include:
- Taxanes such as paclitaxel and docetaxel
- Camptothecan analogs e.g, Irinotecan
- Vinca alkaloids like vinblastine and vincristine
5. Mitotic Inhibitors
They are also made from natural products. They interfere with the division of the cells thus affecting the multiplication of cancer cells.
6. Topoisomerase Inhibitors
These drugs work by preventing enzymes that are necessary for cell multiplication from reaching the cancer cells to prevent them from multiplying.
This class contains other drugs that do not fit into other categories. They are unique in their nature.
What Factors Determine the Type of Chemotherapy to be Used?
The type of chemotherapy that will be used to treat your illness will depend on quite a number of variables. Examples of such factors may include the following:
- Which type of cancer do you have?
- How far has the cancer spread in your body?
- What is the general state of your health?
- How old are you?
- The appearance of cancer cells when viewed under a microscope.
Are There any Types of Chemotherapy which do not Cause Side Effects?
There are no specific chemo treatment drugs that do not cause side effects. Each type of drug has its own side effects. The side effects differ from person to person and they also depend on the combination of drugs that are used in the treatment and the extent to which the chemotherapy drugs cause damage to your normal healthy cells.
Some of the side effects may include:
- Diarrhea- Diarrhea must be treated soon as it can lead to dehydration quickly.
- Nausea and vomiting
- Mouth and sore throats. This mostly happens for a few days once the treatment has begun. Always be careful to avoid the sores from getting infected.
- Pain- Chemotherapy can cause a lot of pain especially when it damages the nerves.
- Being fatigued- Fatigue arises from reduced red blood cells due to the chemotherapy. Hence less oxygen reaches your blood cells making you feel tired more often.
- Sexual complications- Chemotherapy can interfere with a person’s sexual effectiveness. This can cause a lot of problems in a person’s personal life.
Fortunately most of these side effects will go away after the treatment is over.
The Bottom Line
There are several types of chemotherapy and the kind of treatment that will be used will be based on the type of cancer you have and the extent of its spread. You should always ensure to discuss on the type of treatment to be undertaken with your doctor.
Learn the side effects and keep in touch with the doctor at all times. Share any information concerning your medical history with your doctor and also make sure to stick with your treatment schedule.
- Categories of chemotherapy drugs
- Types of chemotherapy
- Side effects of chemo treatment drugs