Both of the combinations or single chemotherapy drug can be used in late-stage breast cancer patients. Nevertheless, most of the oncologists today prefer to use single chemotherapy drug at one time for their patients. Current research suggests that although combination therapy may offer a slightly longer delay in progression during late-stage, it do not provide clear improvement in length of survival. Moreover, the considerable cost of combination of a few drugs is also one of the concerns during making choice of treatment. For these reasons, single agent is often preferred, rather than combinations of agents.

According to Ann H. Partridge, M. D., M.P.H., a medical oncologist at Dana- Farber Cancer Institute specializing in breast cancer, chemotherapy combinations are used either as part of clinical trial or in crisis situations, such as if the cancer cells grow very rapidly and interfere with organ function.

Otherwise, most of the oncologists prefer to use single chemotherapy drug or a single agent paired with the medication Herceptin if the cancer is HER2/ neu-positive. (Herceptin is a monoclonal antibody which designed to target the HER2/ neu protein receptors on the cancer cells.

In the treatment of breast cancer using single chemotherapy drug, when the cancer cells stop responding to a particular drug, it is usually discontinued and replaced by another new chemotherapy drug. This strategy can effectively stop the further growth of the cancer cells and possibly shrink existing tumors.

Treatment for late-stage cancer may be daily, weekly or monthly, depending on the drugs used. The tolerance of patients towards the side effects of drugs is one of the considerations too. During the selection of drugs, the drug with fewer side effects is usually started to be used. However, it may different for each patient since the response is individual.