Chemotherapy for Breast Cancer
Chemotherapy is treatment for breast cancer using drugs. The type of drugs used are cytotoxic, which means they destroy certain cells, and in this case, cancer cells. The drug circulates through the bloodstream and can reach the cancer wherever it might be in the body. It targets cells that are actively growing by dividing, and as it cannot differentiate between cancer cells and normal cells, some normal cells may be destroyed as well. However, as cancer cells are more likely to be dividing than normal cells, these are more likely to be affected. As cancer cells are essentially ‘DNA damaged’ they cannot repair themselves like normal cells, which can often repair the damage caused by chemotherapy.
Chemotherapy may be prescribed as a pre-surgery treatment to reduce the size of the cancerous tumour prior to surgery. Reducing the size of the tumour before surgery could mean less surgery may be required. The surgeon may be able to remove just the lump and not the whole breast if the tumour has decreased in size.
It may also be prescribed as post-surgery treatment to prevent cancer from returning. It might be advised as a treatment if cancer cells were found in the lymph nodes under the arm, if there was a large primary cancer tumour in the breast, if the cancer cells were high grade such as grade 3, and if the cancer cells did not show a significant response to hormone therapy.
If cancer cells had broken off from the tumour and moved elsewhere in the body via the bloodstream or lymphatic system, chemotherapy would be used to kill these cells as it can reach cancer cells anywhere in the body because it travels in the bloodstream. This course of treatment may be prescribed to prevent cancer coming back.
Chemotherapy, like hormone therapy, reduces the production of oestrogen in the body. Oestrogen can stimulate the growth of some breast cancer cells so by reducing or removing the supply of oestrogen this can be prevented.