How is breast cancer chemotherapy given?

In most cases, chemotherapy is most effective when combinations of more than one drug are used. Many combinations are being used, and it's not clear that any single combination is clearly the best. Clinical studies continue to compare today's most effective treatments against something that may be better.

Doctors give chemotherapy in cycles, with each period of treatment followed by a rest period. The chemotherapy begins on the first day of each cycle, and then the body is given time to recover from the effects of chemotherapy. The chemotherapy drugs are then repeated to start the next cycle. The time between giving the chemotherapy drugs is generally 2 or 3 weeks and varies according the specific chemotherapy drug or combination of drugs. Some drugs are given more often. These cycles generally last for a total time of 3 to 6 months when given as adjuvant therapy, depending on the drugs used. Treatment may be longer for advanced breast cancer.

Dose-dense chemotherapy: Doctors have found that giving the cycles of chemo closer together can lower the chance that the cancer will come back and improve survival in some women. This usually means giving the same chemo that is normally given every 3 weeks, but giving it every 2 weeks. In addition, a drug (growth factor) to help boost the white blood cell count is given after the chemo to make sure the white blood cell count returns to normal in time for the next cycle. This approach can lead to more side effects and be harder to take, so it is only used for adjuvant treatment in women with a higher chance of the cancer coming back after treatment. Recently, this approach was also used for neoadjuvant therapy. The patients getting treated more often had their tumors shrink more, were less likely to have the cancer come back, and lived longer than the patients treated every 3 weeks.