Medical professionals typically administer chemotherapy medications in cycles. The duration of each cycle depends on several factors, such as the types of chemotherapy drugs used, the type of cancer a person has, and its response to the medication.
Chemotherapy is a cancer treatment that involves administering medications to kill cancer cells or stop them from growing.
This article outlines some common types of chemotherapy, and provides information on the duration of chemotherapy treatment and cycles. We also outline some of the different methods for administering chemotherapy medications and possible side effects.
For chemotherapy to start working, the medications must first reach the cancerous cells. Scientists do not know exactly how long this process can take.
Some forms of chemotherapy may be faster-acting than others. For example, a person must ingest and digest oral chemotherapy medications before the drugs can enter the bloodstream. By contrast, a person can rub topical chemotherapy medications directly onto cancerous cells.
The length of a person’s chemotherapy sessions will depend on the type of chemotherapy they receive.
For instance, ingesting oral medications may take only a few seconds, whereas receiving IV treatments could take anywhere from several minutes to several days.
Chemotherapy often involves several sessions or “cyles” of treatment. A cycle of chemotherapy is the amount of time that elapses between the start of one round of chemotherapy to the start of the next.
Cancer Research UK states that it is very important for a person to receive their chemotherapy treatment in cycles. While chemotherapy drugs kill cancer cells, they also kill fast-growing healthy cells within the body. Receiving chemotherapy in cycles helps to effectively kill off the cancerous cells, while allowing the person’s body time to replenish its healthy cells.
A single course of chemotherapy will typically involve four to eight chemotherapy cycles. For instance, a 4-week cycle could involve someone taking medications on the first, second and third days, then no further medication until the 29th day.
A doctor will decide the length and structure of a person’s chemotherapy cycles.
Chemotherapy treatment typically lasts between 3–6 months. However, some people will receive chemotherapy for shorter or longer periods of time.
Factors affecting chemotherapy duration
Cancer Research UK notes that the length of a person’s chemotherapy treatment and the structure and length of their cycles depends on the following factors:
- the type of cancer and its stage
- the chemotherapy medications the doctor prescribes
- the cancer’s response to the medications
- the nature and severity of side effects from the medications
Since chemotherapy drugs can harm healthy cells, a person needs to excrete as much chemotherapy medication as possible before receiving another treatment cycle.
Different chemotherapy drugs remain in the body for different amounts of time. Some examples are as follows:
- interactions between the chemotherapy drugs and any other drugs the person is taking
- liver or kidney dysfunction caused by tumors or cancers
- liver or kidney dysfunction caused by cancer therapies
Chemotherapy involves administering chemotherapy drugs to kill cancer cells or prevent their growth.
There are many types of chemotherapy medication. Medical professionals classify these medications according to their chemical structure and how they work. The different classes of chemotherapy medication include:
- Alkylating agents: Damage the cancer cell’s DNA to stop it from making copies of itself and reproducing.
- Antimetabolites: Interfere with DNA and RNA production to stop cancer cells from reproducing.
- Anti-tumor antibiotics: Bind with the cancer cell’s DNA so that it cannot make copies of itself and reproduce.
- Topoisomerase inhibitors: Enzymes called “topoisomerases” help separate DNA strands for replication. Topoisomerase inhibitors bind with topoisomerases, thereby stopping cancer cells from reproducing.
- Mitotic inhibitors: Prevent enzymes from making the proteins necessary for cell reproduction.
A person may receive a chemotherapy drug on its own or in combination with other chemotherapy drugs. Medical professionals can administer chemotherapy medications in the following ways:
- orally, in the form of pills, capsules, or liquids
- topically, in the form of gels, creams, or ointments
- via injection into a body part
- via an intravenous (IV) drip
A doctor will be able to indicate what the person can expect before undergoing their first chemotherapy session. These expectations will depend on different factors, such as the types of chemotherapy drugs the doctor prescribes and their method of administration.
The American Cancer Society (ACS) provides some useful information about the more common chemotherapy treatment types, as follows:
Oral chemotherapy involves ingesting pills, capsules, or liquid medicines.
People receiving this form of chemotherapy may take these medications at home, although they must do so according to a pre-arranged schedule.
Some chemotherapy drugs require careful handling and storage. A person should talk with their doctor about any special considerations when handling or storing their medications.
Topical chemotherapy involves applying gels, creams, or ointments to an area of skin that contains cancerous cells.
People can apply these topical treatments at home and according to a pre-arranged schedule.
As with oral chemotherapy, anyone using topical chemotherapy drugs should exercise caution when handling and storing these medications. In particular, they may need to wear gloves when applying certain topical treatments.
Injectable and IV chemotherapy
Injectable and IV chemotherapy involves administering chemotherapy medication directly into a vein or other body part.
A medical professional must first place a soft plastic tube or “catheter” into a person’s vein when administering IV chemotherapy. The catheter connects to a syringe or plastic bag that contains the chemotherapy medications. These medications then pass through the syringe or IV line, through the catheter, and into the person’s bloodstream.
People can receive injectable and IV chemotherapy in one of the following settings:
- a doctor’s office
- the person’s own home
Chemotherapy drugs work by attacking fast-growing cancer cells. However, these drugs can also attack fast-growing healthy cells. This causes chemotherapy side effects.
Some common chemotherapy side effects include:
- hair loss
- nausea and vomiting
- appetite changes
- weight changes
- constipation or diarrhea
- sores on the throat, tongue, or mouth
- bruising or bleeding more easily than usual
The ACS and the National Cancer Institute provide some helpful resources for people experiencing chemotherapy side effects.
Chemotherapy is a form of cancer treatment that involves administering medications to kill cancer cells or prevent them from replicating.
There are many types of chemotherapy drugs available, and each may have a different method of administration. Medical professionals typically administer these drugs in cycles. This enables the drugs to effectively kill off the cancerous cells, while allowing the person’s body time to replenish any healthy cells that died during the treatment cycle.
Chemotherapy drugs kill fast-growing cells, regardless of whether the person’s cells are cancerous or healthy. The death of healthy cells can cause chemotherapy side effects. Individuals should talk with their doctor or treatment team for advice on managing these side effects.