The treatment of most cancers involves 2 components:
Local treatment – aimed at controlling the primary tumour (for example surgery, to remove a cancerous breast lump)
Systemic therapy – treatment that works throughout the body, to control tumour cells wherever they may be.
Systemic therapy refers to all the medications that are used to treat cancers. These treatments may be given intravenously, or orally, and are distributed around the body by the bloodstream.
There are many different drugs which fall into the category of systemic therapy and these can be grouped into 4 broad categories:
1) Conventional chemotherapy drugs – these work primarily by interfering with mechanisms by which cells divide. They affect both cancer cells and normal cells, but the normal cells are able to repair much of the damage caused by the chemotherapy drug; or they are less affected by it, due to the fact that they are dividing less rapidly than the cancer cells. Side effects of chemotherapy drugs vary considerably but, in most cases, the side effects are largely related to their impact on more rapidly dividing normal cells.
2) Targeted therapies – these drugs work by targeting molecules which are either specific to particular cancers or occur more frequently in cancer cells, than normal cells. These targeted treatments generally have fewer side effects than conventional chemotherapy drugs, due to their ability to target cancer cells more specifically.
3) Hormonal therapies – these treatments work by either 1) blocking the production of certain hormones or 2)blocking the receptors to which hormones bind to on cancer cells. These treatments are used mainly in cancers which are hormonally driven (such as prostate cancers; some breast cancers and some gynaecological cancers).
4) Immunotherapy – these treatments work by either helping the immune system “recognize” the cancer cells more easily (and thereby assist in killing the cells) or by stimulating the immune system to become” hyperactive”. As cancer cells are our own cells which are “out of control” the immune system very often doesn’t see these cells as being foreign and therefore needs additional help in order to play a role in cancer management.
As there are many different types , and subtypes, of cancer (each of which have unique characteristics) the type of systemic therapy used, will be different for each individual.
The type of drug (or combination of drugs); the way in which they are given and possible side effects will be discussed, in detail, with you by your oncologist (and again by the chemotherapy sisters) prior to starting your treatment.
It is important to point out that other medications; supplements and alternative therapies may interact with your systemic treatment. These interactions may reduce the efficacy of the treatment, or increase side effects. You should not, therefore, take any additional treatments or supplements without discussing them first with your oncologist.
As systemic therapies for cancer have the ability to cause birth defects ( if pregnancy occurs while on treatment) appropriate contraception is essential for all men and women (in their reproductive years) who are on systemic therapy for cancer. Please discuss which options are most appropriate for you, with your oncologist.
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