Before an operation
Chemotherapy can be used before an operation (this is known as neo-adjuvant or primary chemotherapy) to shrink a cancer that is too large – or too attached to surrounding healthy tissue – to be removed easily during an operation. This can make removing the cancer easier during a later operation.
After an operation
Chemotherapy can be given after an operation (this is known as adjuvant chemotherapy) when all the visible cancer has been removed but there is a risk that some cancer cells, which are too small to be seen, may have been left behind. The aim is to destroy these cancer cells.
Chemotherapy may also be given if a cancer cannot be completely removed during an operation. In this situation chemotherapy may not be able to cure the cancer but may shrink it and so reduce symptoms.
During radiotherapy
Sometimes chemotherapy is given at the same time as radiotherapy. This is known as chemoradiotherapy or chemo-radiation.
In advanced cancer
Where cancer has spread into surrounding tissue or other parts of the body (advanced cancer), chemotherapy can sometimes be given with the aim of getting rid of all the cancer and curing it. More commonly however, chemotherapy is given to people in this situation to shrink and control the cancer, to try to extend life and control any symptoms that may occur.
High-dose chemotherapy with bone marrow transplant or stem cell support
For some types of cancer, high-dose chemotherapy is given. This is usually done after initial chemotherapy has got rid of the cancer cells but there is a high risk of the cancer coming back. High doses of chemotherapy would normally destroy the bone marrow – which makes the blood cells – so the bone marrow has to be replaced after the chemotherapy has been given. This is done using stem cells which have been collected from the bone marrow or blood. The stem cells are collected before the high-dose treatment, either from the patient, or from someone else (a donor) whose cells are a good match. They settle in the bone marrow and develop into the different blood cells. This type of treatment is only used in a few types of cancer.
Our section on stem cell and bone marrow transplants discusses this treatment in detail.