Chemotherapy (chemo) uses anti-cancer drugs that may be given intravenously (injected into your vein) or by mouth. The drugs travel through the bloodstream to reach cancer cells in most parts of the body. Occasionally, chemo may be given directly into the spinal fluid which surrounds the brain and spinal cord.
Not all women with breast cancer will need chemo, but there are several situations in which chemo may be recommended :
Adjuvant chemo might be given to try to kill any cancer cells that might have been left behind or have spread but can't be seen, even on imaging tests. If these cells were allowed to grow, they could form new tumors in other places in the body. Adjuvant chemo can lower the risk of breast cancer coming back.
Neoadjuvant chemo might be given to try to shrink the tumor so it can be removed with less extensive surgery. Because of this, neoadjuvant chemo is often used to treat cancers that are too big to be removed by surgery when first diagnosed (called locally advanced cancers). Also, by giving chemo before the tumor is removed, doctors can see how the cancer responds to it. If the first set of chemo drugs doesn’t shrink the tumor, your doctor will know that other drugs are needed. It should also kill any cancer cells that have spread but can't be seen. Just like adjuvant chemo, neoadjuvant chemo can lower the risk of breast cancer coming back.
For certain types of breast cancer, if there are tumor cells still found at the time of surgery (also called residual disease), you may be offered more chemotherapy after surgery to reduce the chances of the cancer coming back (recurrence).
Chemo can be used as the main treatment for women whose cancer has spread outside the breast and underarm area, either when it is diagnosed or after initial treatments. The length of treatment depends on how well the chemo is working and how well you tolerate it.