How do chemotherapy drugs work?

How chemotherapy drugs work

Chemotherapy drugs work by stopping cancer cells reproducing. Different drugs affect the cancer cells in different ways. When a combination of drugs is used, each drug is chosen for its different effects.

Most chemotherapy drugs are carried in the blood. This means that they can reach cancer cells anywhere in the body. But chemotherapy can be given in different ways. This depends on the type of cancer being treated and the chemotherapy drugs being used.

Chemotherapy drugs also affect some healthy cells. These healthy cells can usually recover from damage caused by chemotherapy but cancer cells can’t and eventually die.

Side effects of chemotherapy

The effect chemotherapy drugs have on some of the healthy cells in your body can cause side effects. Most side effects will go away when treatment is over.

Healthy cells in certain parts of the body, such as the bone marrow (which makes blood cells) and the digestive system, are more sensitive to chemotherapy drugs. This is why certain side effects, such as risk of infection or feeling sick, are more common. Side effects can be reduced and managed by following some helpful hints.

Monitoring the effects of the cancer

During treatment your cancer doctor may want to find out how the cancer is responding to the chemotherapy drugs. This can be done in different ways.

  • If a cancer can be felt or is visible your doctor will be able to tell if it’s responding to chemotherapy by doing a physical examination.
  • If the cancer can be seen on a scan, you may have another scan after a few cycles of chemotherapy to see if the cancer is getting smaller. If you’re having chemotherapy to reduce the risk of cancer coming back after surgery (adjuvant chemotherapy) you won’t usually need scans to check if it’s working.
  • With some cancers, blood tests can be used to check if treatment is working. These cancers release proteins in the blood (called tumour markers) that can be measured with a blood test. If the tumour markers are reducing it usually means the chemotherapy is working.

If results show the cancer hasn’t responded well enough, your doctor may decide to change your treatment to different chemotherapy drugs.

Back to Chemotherapy explained

When is chemotherapy used?

Chemotherapy is used to kill cancer cells in the body. Your doctor will explain if chemotherapy is advised for you.