What is Chemotherapy?
Chemotherapy, also known as medical oncology, is a treatment for cancer. It involves the use of drugs usually given in the form of an intravenous injection (delivered into a vein) or drip, but can also be given in the form of a tablet or by introducing drugs directly into a tumour or affected organ. Because it gets into the bloodstream, chemotherapy can treat cancer throughout the body, reaching cancer cells in different organs and tissues.
Chemotherapy works by targeting and killing actively growing cells. Because cancer cells generally grow and divide faster than normal cells, they are more susceptible to the action of these drugs. However, damage to healthy cells is unavoidable, and this damage accounts for the side effects that occur with this treatment. Your medical oncologist and nurse specialist will discuss these side effects with you in detail.
Chemotherapy can be used for different reasons:
- Cure: Some cancers can be cured by chemotherapy on its own or in combination with other treatments such as radiotherapy (concurrent therapy) or surgery
- To help other treatments: Chemotherapy can be given either before or after other treatments. If chemotherapy is used beforehand, its purpose is to make the cancer smaller so your main treatment is more effective (neoadjuvant therapy). If chemotherapy is given after your main treatment, its aim is to get rid of any remaining cancer cells that cannot be seen (adjuvant therapy).
- To control the cancer: If the cancer cannot be cured, chemotherapy can be used to control the cancers growth for an extended period of time.
- Symptom relief (palliation): When the cancer can’t be cured, but causes symptoms such as pain, chemotherapy can provide relief.
Chemotherapy can be given to you in the chemotherapy day unit as an outpatient appointment,
but some more complex treatments may require you to be admitted as an inpatient (involving a stay in hospital). Having chemotherapy should be painless.
Some types of chemotherapy can be administered at home, utilising our Hospital in the Home Service. If you would like to use this service, please discuss your options with your treatment team
Administering intravenous chemotherapy
Administering intravenous chemotherapy can be done via a few different methods.
- Cannula – this is a thin plastic tube about 1.5cm long that is inserted into a vein in your arm or hand. The drugs are then delivered through an intravenous drip attached to the cannula. The cannula is removed once the drugs have been given.
- Central Line – this may also be called a Hickman line, or a porta-cath. It is a semi-permanent drip that goes into a large vein near the heart and can stay for several months if necessary. These lines may be put in place under local anaesthetic, while you are in the x-ray department, or in an operating theatre under a general anaesthetic. A central line can be used to take blood as well as give chemotherapy.
Central lines may be used
- if you need continuous chemotherapy (for example, 24 hours a day, using a small portable pump)
- you are likely to need chemotherapy for a long time
- if the chemotherapy might damage small veins
- it is difficult to put a cannula in your veins.
The central line will be removed once you have finished your chemotherapy.
Length of Chemotherapy Treatment
The length of chemotherapy treatment is determined by a variety of factors. These include the type of cancer, the extent of cancer, the types of drugs that are given, as well as the expected toxicities of the drugs and the amount of time necessary to recover from these toxicities. Many chemotherapy treatment schedules (including the type and length of chemotherapy treatment) have been determined through clinical trials that compared them and determined which had the most benefit and was most well tolerated.
In general, chemotherapy treatment is given in courses or cycles with rest periods in between. This allows normal cells to recover and your body to regain its strength. If your body needs more time to recover, the next cycle may be delayed.
Duration of the cycle: Chemotherapy treatment may be a single drug or a combination of drugs. The drugs may all be given on a single day, several consecutive days, or continuously as an outpatient or an inpatient. Treatment could last minutes, hours, or days, depending on the specific protocol.
Frequency of the cycle: Chemotherapy may repeat weekly, bi-weekly, or monthly. Usually, a cycle is defined in monthly intervals. For example, two bi-weekly chemotherapy sessions may be classified as one cycle.
The number of cycles: In most cases, the number of cycles - or the length of chemotherapy from start to finish - has been determined by research and clinical trials.
As a general guide, adjuvant chemotherapy (therapy after surgery has removed all visible cancer) may last 4-6 months. Adjuvant chemotherapy is common in cancers of the breast and colon. In cancers of the testis, Hodgkin and non-Hodgkin lymphoma, and leukemias, length of chemotherapy treatment may be up to a year.
Other types of drug treatment for cancer
Chemotherapy drugs remain an important part of treatment for most types of cancer. However, many newer cancer drugs target processes that are specific to cancer cells but not normal cells, and therefore have different side effects. They are sometimes used alone but are usually given in combination with traditional chemotherapy.
Hormone therapy: These treatments change the amount of hormones (natural chemicals that circulate in the bloodstream and regulate the activity of certain cells or organs) in the body. Hormone therapy helps because several types of cancer can only grow and spread when certain hormones are present. Hormone therapy does not work for all types of cancer, but can be useful in hormone sensitive or hormone dependant cancers such as breast, prostate, ovarian or kidney.
Targeted therapy: These treatments target specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. As a result, this type of treatment blocks the growth and spread of cancer cells while limiting damage to normal cells. Targeted therapy can be used in some melanoma patients.
Immunotherapy: This type of treatment is designed to boost the body's natural defences to fight the cancer. It uses materials made either by the body or in a laboratory to bolster, target, or restore immune system function.