When you might have chemotherapy
Whether you have chemotherapy as part of your treatment depends on:
- what type of cancer you have
- how big it is
- whether it has spread or not
Surgery only removes the cancer from the area it is in the body. And radiotherapy only treats the area of the body it is aimed at.
Doctors use chemotherapy because it circulates throughout the body in the bloodstream. So it can treat cancer almost anywhere in the body. Chemotherapy is a systemic treatment.
You might have chemotherapy:
- to shrink a cancer before surgery or radiotherapy
- to try to stop cancer coming back after surgery or radiotherapy
- at the same time as other treatments
- as a treatment on its own, if your type of cancer is very sensitive to it
- to treat cancer that has spread from where it first started
- as part of a clinical trial
Before surgery or radiotherapy
The aim of chemotherapy before surgery is to shrink a tumour. This might mean:
- you need less surgery
- it is easier to get all the cancer out
- you can have radiotherapy to a smaller area of your body
Having chemotherapy before other treatments in this way is called neoadjuvant treatment. Sometimes doctors may call it primary treatment.
After surgery or radiotherapy
The aim of chemotherapy after surgery or radiotherapy is to lower the risk of the cancer coming back in the future. This is called adjuvant treatment.
The chemotherapy circulates throughout your body. It kills off any cancer cells that have broken away from the main tumour before your operation.
With other treatments
Sometimes doctors prescribe chemotherapy at the same time as other treatments. You might have it with:
- radiotherapy
- immunotherapy
- targeted cancer drugs
On its own
You might have chemotherapy as a treatment on its own, without surgery. This is for types of cancer that are very sensitive to chemotherapy or if you can't have surgery for your cancer.
For cancer that has spread
Sometimes cancer cells break away from a tumour. They may travel to other parts of the body through the bloodstream or 
.
The cells may settle in other parts of the body and develop into new tumours. These are called secondary cancers or metastases. Chemotherapy drugs circulate in the bloodstream around the body to treat any cancer cells that have spread.
Your doctor might suggest chemotherapy if there is a chance that your cancer might spread in the future. Or if it has already spread.
As part of a clinical trial
Your doctor might offer you chemotherapy as part of a clinical trial. This could be a new drug, or one that is already used to treat other types of cancer.
Clinical trials aim to find out if a treatment:
- is safe
- has side effects
- works better than the currently used treatment
- affects quality of life
Chemotherapy drugs
The chemotherapy drugs you have depend on where in your body the cancer started (your type of cancer). This is because different chemotherapy drugs work on different types of cancer.
So the drugs you need for a cancer that started in the breast and has spread to the lung might be different to the drugs you would have for a cancer that started in the lung.
Why chemotherapy might not be suitable for you
Some cancers are very sensitive to chemotherapy, so it can work very well for them.
But some types of cancer don't tend to respond well to chemotherapy. In that case, your doctor isn't likely to suggest it as a treatment for you.
Chemotherapy can be a difficult treatment to have. You need to have a good level of general health and fitness to have it.
Some people worry they may be too old to have chemotherapy. No one is automatically too old. But older people may have other health issues that make them more likely to get severe or long term side effects.
Some treatments can put a strain on organs such as the heart. Doctors make sure you are well enough by checking your heart, lungs, kidneys and liver before starting treatment.
They discuss the benefits and risks of any treatment with you when deciding your treatment plan.
