NOT THE SAME AS PREVENTING CANCER
To prevent the development of cancer, lifestyle changes are needed, such as diet, exercise and use of sunscreen.
Tamoxifen, a hormone therapy drug, can be used to prevent the risk of cancer for patients at high risk of developing breast cancer.
Aspirin can also be used for those with a high risk of stomach cancer or other types of cancer.
However, in terms of cancer therapy, preventive chemotherapy is giving chemotherapy after the cancer has been removed to prevent the cancer from appearing again.
If the cancer is localized (limited to certain parts of the body) without any evidence of spread to other parts of the body, then treatments such as surgery or radiotherapy can remove all the cancer cells.
However, if the cancer is first detected after it has spread to other parts of the body at the time of diagnosis, the doctor will carry out treatment such as chemotherapy (anti-cancer drugs), hormones or immunotherapy, which is circulated throughout the body.
Another use of chemotherapy is to add it before or after surgery or radiotherapy, to prevent the primary cancer from returning. Surgery may have cured the cancer. However, in some cases, undetected microscopic cells may have spread into the bloodstream to distant parts of the body. This will cause the cancer to reappear months or years later.
In some types of cancer, treatment with chemotherapy, given before or after local surgery or radiotherapy, can kill the cells and prevent the cancer from returning.
Cells cannot be seen, so how do we know the cancer will not come back by giving additional chemotherapy? We have learned this from clinical trials. Researchers have compared patients who underwent surgery alone, with patients whose surgery was followed by additional chemotherapy (or often called adjuvant chemotherapy). This additional chemotherapy was successful in preventing the cancer from returning and the patient survived longer.
