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 and whether it has spread or not.

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.

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. 

You might 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, if your type of cancer is very sensitive to it 
  • to treat cancer that has spread from where it first started 

Before surgery or radiotherapy

The aim of chemotherapy before surgery is to shrink a tumour so that you need less surgery, or to make it easier to get all the cancer out. Shrinking the cancer with chemotherapy might also mean that 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 and kills off any cancer cells that have broken away from the main tumour before your operation.

For blood cancer

You might have chemotherapy as a treatment on its own, without surgery. This is for types of cancer that are very sensitive to chemotherapy, such as blood cancer.

For cancer that has 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. 

Sometimes cancer cells break away from a tumour. They may travel to other parts of the body through the bloodstream or lymphatic system. 

The cells may settle in other parts of the body and develop into new tumours. These are called secondary cancers or metastases. The drugs circulate in the bloodstream around the body to treat any cancer cells that have spread. 

With radiotherapy

Sometimes doctors prescribe chemotherapy at the same time as radiotherapy. This is called chemoradiotherapy or chemoradiation. It can make the radiotherapy more effective, but can also increase side effects.

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, and you need to be well enough 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 fit enough by checking your heart, lungs, kidneys and liver before starting treatment.

They look at the benefits and risks of any treatment when deciding your treatment plan, and will discuss this with you.

  • Cancer and its Management (7th edition)

    J Tobias and D Hochhauser

    Wiley Blackwell, 2015

  • Handbook of Cancer Chemotherapy (8th edition)
    R T Skeel and S N Khleif
    Lippincott, Williams and Wilkins, 2011

Last reviewed: 
11 Jun 2020
Next review due: 
11 Jun 2023