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Breast Cancer Drugs

Breast Cancer Drugs

Your doctor will determine your breast cancer treatment after considering multiple factors like the specific type and stage of the cancer. According to the Mayo Clinic, many women diagnosed with breast cancer undergo surgery as a part of their treatment. There are also numerous drugs for breast cancer that may be used before, after, or in some cases, instead of surgery.

There are many different options, and the complex decision-making may be very overwhelming. Communicating with your doctor is key.

Trastuzumab (Herceptin)

Trastuzumab, more commonly known by its brand name, Herceptin, is a targeted therapy for breast cancer.  According to the American Cancer Society, Herceptin can stop the growth and spread of breast cancer by stopping the human epidermal growth factor receptor 2 (Her-2/neu) actions on cancer cells. Herceptin is given through an IV. It’s most often used in combination with chemotherapy or hormone therapy. It’s known as a targeted therapy because it specifically attaches to the protein that is driving the growth of Her-2/neu positive breast cancers.  This attachment slows growth of the cancer by blocking one of the signals for cancer cells to divide and labels only those cells for killing by the patient’s own immune system. It does not damage any other cells.

The Herceptin regimen usually calls for an initial 90-minute dose. Follow-up dosages of shorter duration happen a week to three weeks later. Studies haven’t yet proven the most effective duration. Herceptin can cause negative side effects for some patients. The U.S. Food and Drug Administration (FDA) requires that patients be screened for proper heart function before undergoing Herceptin treatment.  Also, if you already have lung disease like asthma or COPD or if the breast cancer has significantly invaded your lungs, there is an increased possibility of lung damage. Your doctor should go over side effects that may occur before you start this treatment.

Lapatinib (Tykerb)

Like Herceptin, Tykerb targets the HER2 receptor. But unlike Herceptin, it interferes with the action of the receptor inside the cell rather than blocking its activation outside the cell.  Because of this difference, Tykerb only slows down tumor growth. It does not label the cells for removal by the patient’s immune system.  It’s approved for the treatment of advanced metastatic breast cancer. But it’s typically reserved for women who have already tried Herceptin without positive results.

Side effects of Tykerb reflect this somewhat more generalized activity and include vomiting, diarrhea, nausea, fatigue, rash, mouth sores, and pain in the hands and feet (neuropathy).

Bevacizumab (Avastin)

Avastin is a drug therapy that starves cancer cells by preventing the tumor cells from communicating with nearby blood vessels and may prevent the tumor from connecting to the blood supply. The cancer cells die without a blood supply bringing fresh oxygen and nutrients to the tumor.

Side effects of bevacizumab include fatigue, high blood pressure, blood clots, headaches, heat damage, and mouth sores.

The U.S. Food and Drug Administration approved bevacizumab in 2004. In 2008, it was approved for use in metastatic breast cancer. There was some controversy around this. The panel advised against approval because while the drug may help slow the growth of cancer cells, research hasn’t been able to show the drug can increase a person’s survival rate. In 2011, the FDA revoked the use of the drug in advanced breast cancer.

Doctors can still prescribe it for "off-label use," but insurance companies are less likely to cover it. In 2014, the FDA approved use of bevacizumab in patients with aggressive and late-stage cervical cancer.

Chemotherapy Drugs

According to the American Cancer Society, dozens of chemotherapy drugs are approved by the FDA for the treatment of breast cancer. Certain chemotherapy drugs for breast cancer are used more commonly than others.

  • Cyclophosphamide (Cytoxan) blocks the copying of DNA in cancer cells, inhibiting their growth.
  • Docetaxel (Taxotere) interferes with cell division, slowing the disease’s progression.
  • Doxorubicin (Adriamycin) is an anthracycline drug, which is derived from strep bacteria and is one of the more effective broad spectrum chemotherapy agents.
  • Fluorouracil (Adrucil) blocks enzymes required for DNA production by cancer cells.
  • Methotrexate (Trexall) blocks an enzyme needed by cancer cells (and other rapidly dividing cells) to live.
  • Paclitaxel (Taxol), a taxane like docetaxel, disrupts cell division.

Chemotherapy regimens often combine the agents above and others. Doses typically include two or more drugs to enhance their power and to decrease the chance that the cancer will return. The expectation is that combination therapy will allow many women with breast cancer to live longer.

One combination that is gaining favor among clinicians is aimed at women whose estrogen receptor-negative breast cancer has spread to the lymph nodes. For them, many oncologists prescribe an anthracycline such as cyclophosphamide followed by a taxane (docetaxel or paclitaxel). This combination has been shown to reduce the chance of a relapse and to provide a longer life for the women who take it.

A similarly population-specific treatment is for women with Her-2/neu positive cancer. A course of chemotherapy used together with Herceptin (trastuzumab) significantly decreases the risk of recurrence and even improves chances for increased longevity.

Side effects may occur with any chemotherapy drug. Side effects will differ depending on differences in regimens, drugs, and the individual. Common side effects include:

  • hair loss
  • digestive tract complications
  • mouth sores
  • low blood counts
  • fatigue
  • easier bruising
  • infection

Before you begin any chemotherapy, your medical team should go over side effects that may occur and suggestions to combat or mitigate them.

Hormone Therapy


This synthetic hormone decreases the risk of recurrence in women with either early-stage or metastatic hormone receptor-positive breast cancer. Tamoxifen blocks estrogen, which reduces the chances for recurrence or new tumor development. It’s appropriate for both pre- and postmenopausal women who have hormone receptor-positive breast cancer. Tamoxifen won’t work for breast cancers that are not estrogen-sensitive or for women who do not have an enzyme, CYP2D6, which activates the drug.

Tamoxifen is usually given daily for five years. So far this appears to be the optimal length of treatment. Side effects from it are usually irregular periods, vaginal discharges, and hot flashes. There is also a low risk for leg or lung blood clots and different kinds of uterine cancer.

Aromatase Inhibitors

Postmenopausal hormone receptor-positive women are the prime candidates for aromatase inhibitor (AI) therapy. AI drugs include:

  • Anastrozole (Arimidex)
  • Exemestane (Aromasin)
  • Letrozole (Femara)

All three work by prompting a significant drop in your body's estrogen levels. AIs can work as well as tamoxifen and are often used in combination with it. AI drugs can be used alone if a woman cannot take tamoxifen. Many cancer specialists recommend that adjuvant therapy for hormone receptor-positive breast cancer in postmenopausal women include an aromatase inhibitor to reduce the chances for recurrence.

Possible long-term effects of the lowered estrogen caused by both tamoxifen and AI therapy could put you at greater risk of osteoporosis. Your doctor may monitor your bone mineral density while you're taking the medication. Lower estrogen levels also may lead to vaginal dryness and irritation.

Content licensed from:

Written by: the Healthline Editorial Team
Medically reviewed on: Sep 02, 2014: Kenneth R. Hirsch, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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