Chemotherapy

Chemotherapy uses medications given either by mouth or by injection into a vein to kill cancer that may have spread beyond the original tumour. The chemotherapy is usually given in cycles that typically last 21 to 28 days; the average number of cycles ranges from 4 to 8. The medications are usually given in combination, with an average of 2 to 3 different medications taken with each cycle.

Chemotherapy mainly works by killing cells that multiply at a fast pace, like cancer cells. However, the chemotherapy cannot tell the difference between normal cells and cancer cells and therefore it can also kill healthy cells that divide quickly. These cells can include the ones found in your hair, the ones lining your digestive system (from your mouth to your colon), and the ones in your bone marrow. Some chemotherapy agents affect these cells more than others, and the higher the dose of chemotherapy that you receive, the more likely you are to have side effects. For this reason, many people receiving chemotherapy will experience some side effects (discussed in the section on complementary and alternative medicine); however, there are many new medications now that can help to reduce your chances of having some of these side effects or reduce the severity with which you experience them.

Some common chemotherapy agents used for breast cancer include:

• anthracyclines (e.g., doxorubicin, epirubicin)
• cyclophosphamide
• fluorouracil (5-FU)
• methotrexate
• taxanes (e.g., paclitaxel and docetaxel)