Chemotherapy

Chemotherapy

Chemotherapy regimens are designed to kill cancer cells throughout the body. It has advantages for nearly every patient regardless of whether the cancer is hormone receptor-positive or negative.

Adjuvant and Neoadjuvant Regimens

Adjuvant chemotherapy is used after surgery, radiation, or both. Its goal is to eradicate microscopic disease in other parts of the body. Neoadjuvant chemotherapy, which is given before other treatments, is also proving to be useful for women with locally advanced breast cancer (Stage III). In such cases, it may reduce the tumor size so that it is operable.

Candidates for Adjuvant Chemotherapy. Chemotherapy after surgery (adjuvant chemotherapy) is an appropriate consideration for most women with invasive breast cancer, regardless of menopausal status. Studies report that adjuvant therapy may also benefit women with early-stage cancers. Chemotherapy needs to be tailored to the type of cancer involved. Women require different treatments depending on whether the tumor is node-negative or -positive, and whether the cancer is hormone receptor-positive or -negative.

A 2006 study in the Journal of the American Medical Association indicated that women with hormone receptor-negative cancers respond better to chemotherapy than women with hormone receptor-positive cancer. However, some women with hormone receptor-positive cancer do benefit from chemotherapy. Adjuvant hormonal therapy is also an important treatment for women with hormone receptor-positive cancer.

Chemotherapy Regimens and Drug Combinations. Adjuvant chemotherapy is usually administered after initial surgery in combination regimens in four to six courses of treatment over 3 - 6 months and usually before follow-up radiation therapy to the breast.

The following are some important drugs used in combination treatments:

• Anthracyclines. Anthracyclines include doxorubicin (Adriamycin) or epirubicin (Ellence). To date, combinations using these drugs have the best survival benefits. Patients who overexpress the HER-2/neu gene and have hormone receptor-negative tumors may particularly benefit from anthracyclines. The drug may have toxic effects on the heart, however.
• Cyclophosphamide, 5-fluorouracil (5-FU), and methotrexate (CMF). This was the standard regimen for years, but its use has declined with the introduction of anthracyclines. A variation in which mitoxantrone (Novantrone) replaced methotrexate may offer better survival rates than CMF.
• Taxanes include paclitaxel (Taxol) and docetaxel (Taxotere). Two studies published in 2003 suggested that women should strongly consider taxane-based therapy for node-positive breast cancer. The first study compared the standard regimen of 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC) to the combination of docetaxel (Taxotere), doxorubicin (Adriamycin), and cyclophosphamide (Cytoxan) (TAC). After 55 months of follow-up, TAC-treated patients had a 28% lower risk of relapse and a 30% lower mortality rate than FAC-treated patients. In the second study, TAC therapy given on a dose-dense schedule (every 2 weeks) was shown to be superior to a standard schedule (every 3 weeks).
• An injectable suspension form of paclitaxel (Abraxane) uses a novel technology to deliver chemotherapy to the tumor site. In a 2003 study, Abraxane increased the efficacy of paclitaxel by doubling the response rate (33% vs. 19%) and significantly prolonging the time to tumor progression. Abraxane is associated with fewer side effects than paclitaxel, and does not require pretreatment with a steroid. It was approved by the FDA in 2005.
• Trastuzumab (Herceptin). Trastuzumab is a humanized monoclonal antibody that targets the HER2 protein. (Targeted therapies are increasingly showing promise for treating many forms of cancer.) Research supports that trastuzumab, a drug used to treat metastatic breast cancer, is also an important treatment for early-stage, HER 2-positive breast cancer. Trastuzumab is given either along with or following adjuvant chemotherapy. Data from 2005 and 2006 indicate that trastuzumab and paclitaxel plus standard adjuvant chemotherapy (such as doxorubicin and cyclophosphamide) prolongs disease-free survival and reduces the risk of cancer recurrence for these patients. Most of the study patients had cancer that had spread to the lymph nodes (lymph-node positive cancer). In a 2005 study, patients in the trastuzumab treatment group had a 52% reduction in disease recurrence compared with those not treated with the drug. Trastuzumab can cause heart failure and other heart function problems, which can usually be controlled with medication. Women who take trastuzumab need to have regular cardiac monitoring, especially if they have pre-existing heart problems.