Chemotherapy, a treatment that uses drugs to kill cancer cells in the body, is often used to treat breast cancer. There are numerous chemotherapy drugs which doctors might prescribe alone or in combination for patients with breast cancer. The most common breast cancer chemotherapy drugs are anthracyclines, taxanes, and cyclophosphamide.
Patients with breast cancer commonly receive chemotherapy as an adjuvant therapy. Chemotherapy is given in addition to other treatments, such as surgery, to decrease the risk of the cancer returning. The age and health of the patient, the type of tumor, and whether the cancer has invaded the lymph nodes are common factors considered by oncologists in determining the appropriate breast cancer chemotherapy drugs.
Anthracyclines are a class of chemotherapy drugs derived from Streptomyces bacteria. This class of drugs includes doxorubicin, epirubicin, and liposomal doxorubicin. Anthracyclines work by blocking DNA production within cells, thereby preventing the replication of cells. The drug cannot distinguish between cancer cells and healthy cells. Anthracycline drugs have a greater negative effect on cancerous cells than normal cells because of cancel cells divide more rapidly.
Taxanes are a class of chemotherapy drugs derived from a certain species of coniferous yew tree of the genus Taxus. This family of drugs is one of the most well known chemotherapy drugs in existence, and includes docataxel and paclitaxel. Taxanes work by slowing down cell division and preventing enzymes from making the proteins that cells need to grow.
Cyclophosphamide is a synthetic agent that slows or stops cell growth, and therefore stops cancer cells from replicating. This drug also decreases the immune system response to certain conditions. Some patients experience fewer side effects from cyclophosphmide drugs as compared to other chemotherapy drugs.
Breast cancer treatment usually consists of "cocktails" of combined chemotherapy drugs. The most common combinations of breast cancer chemotherapy drugs are anthracycline and cyclophosphamide (AC), taxane and cyclophosphamide (TC), anthracycline, cyclophosphamide, and Taxol® (AC + Taxol®), and anthracycline and taxane (AT). The initials are widely used in the medical community.
AC chemotherapy is the most common drug combination given to patients with breast cancer where the cancer has not spread to the lymph nodes. These treatments are normally given by intravenous (IV) and take about two hours to complete. Programs vary by patient, but most receive four AC treatments, one every three weeks.
TC is one of the most commonly prescribed breast cancer chemotherapy drugs for women with early-stage breast cancer. This therapy has fewer serious side effects than AC chemotherapy. TC chemotherapy typically consists of four to six treatments, one every three weeks, by IV.
AC + Taxol® consists of four AC treatments, given by IV, followed by four treatments of a taxane. This treatment is typically ordered for patients where the cancer has spread to one or more lymph nodes and for patients who have had a recurrence. Taxol® is the most common taxane used in this drug combination.
AT chemotherapy is given to patients that are node-positive. This means that the cancer has spread to their lymph nodes. Patients typically receive a course of six injections of AT chemotherapy.