When chemotherapy is used

This page tells you about when chemotherapy is used to treat cancer. It has information about

When chemotherapy is given
Why chemotherapy is used
Why chemotherapy is not always used

You may have chemotherapy

To shrink a cancer before surgery or radiotherapy
To try to stop cancer coming back after surgery or radiotherapy
As a treatment on its own in cancers that are very sensitive to chemotherapy
To treat cancer that has spread from where it first started

You may have chemotherapy before surgery. The aim is to shrink your tumour so that you need less surgery or to make it easier for your surgeon to get all the cancer out. Or you may have chemotherapy so that you only need radiotherapy to a smaller area of your body. Chemotherapy given before other treatments in this way is known as neoadjuvant treatment. Sometimes this is called primary treatment.

You may have chemotherapy after surgery or radiotherapy. The aim is to lower the risk of the cancer coming back in the future. Chemotherapy circulates throughout the body and kills off any cancer cells that have broken away from the main tumour before your operation. In this situation it is known as adjuvant treatment.

Chemotherapy may sometimes be given at the same time (concurrently) as radiotherapy. This is known as chemoradiation. It can make the radiotherapy more effective, but can also increase the side effects that you may have.

Chemotherapy may be given if there is a chance that your cancer may spread in the future. Or if it has already spread. Doctors use chemotherapy because it circulates throughout the body in the bloodstream. It is a type of systemic treatment. So chemotherapy can treat cancer cells almost anywhere in the body. Surgery and radiotherapy are known as local treatments because as they only affect the area of the operation or the area the radiotherapy is directed at.

Sometimes cancer cells break away from a tumour. They may travel to other parts of your body through your bloodstream or lymphatic system The cells may settle in other parts of your body and develop into new tumours. These are called secondary cancers or metastases. The drugs circulate in the bloodstream around the body.

The chemotherapy that you have is specific to where in your body the cancer started. This is because different chemotherapy drugs work on different types of cancer. So the chemotherapy you need for a cancer that started in your breast and has spread to the lungs would be different to the chemotherapy you need for a cancer that started in the lung.

Some types of cancer are very sensitive to chemotherapy and so it can work very well for those cancers. But some cancers are not sensitive to chemotherapy, and so chemotherapy is not used to treat them.