Systemic therapy is a treatment given by mouth or injected into the bloodstream that can reach cancer cells anywhere in the body. Men with breast cancer may be treated with different types of systemic therapies including chemotherapy, hormonal therapy, or targeted agents — or with combinations of these.

Adjuvant Systemic Therapy

Some patients who have been treated with surgery may also receive adjuvant systemic therapy. The goal of adjuvant treatment is to rid the body of any cancer cells that may have spread outside of the breast and to prevent these from forming new tumors, called metastases, in the future. Adjuvant therapy is usually given after the surgery, but in some cases it is given before the surgery to help shrink the tumor and make it easier to remove (called neo-adjuvant therapy).

A number of factors determine if a male breast cancer patient needs adjuvant therapy and, if so, which type of therapy will be most effective for his particular cancer. These factors include the presence or absence of cancer cells in his lymph nodes, the size of the tumor, and whether his tumor contains hormone receptors or overproduces certain proteins such as HER2/neu. Clinical trials of new treatments for breast cancer are also available.

Systemic Therapy for Treatment of Metastatic Disease

Systemic therapy is also given to patients whose disease has spread from the breast to other organs (metastatic, or stage 4, disease). For adjuvant therapy, the choice of treatments is made based on each patient’s individual disease and takes into account factors such as the tumor’s characteristics and location.

Patients with metastatic disease can ask their doctor to find out if there is an appropriate clinical trial available to them.


Chemotherapy drugs work by interrupting the cell’s growth. In treating breast cancer, doctors often use a combination of two or three drugs at one time. Common chemotherapy drugs for breast cancer include:

Common combinations include:

  • AC (doxorubicin, cyclophosphamide)
  • AC-T (AC followed by paclitaxel)
  • CMF (cyclophosphamide, methotrexate, 5-fluorouracil)
  • TC (docetaxel, cyclophosphamide)
  • TCH (docetaxel, carboplatin, trastuzumab)

Hormones are made by glands in the body and then released into the bloodstream. Hormonal therapies take advantage of the fact that some cancers need certain hormones, such as estrogen, to grow.

About nine in ten men with breast cancer have tumors that are estrogen-receptor (ER) positive, which means that they grow in response to estrogen. These men can be treated with tamoxifen, a drug that targets the estrogen receptor and also is common for treatment of female breast cancer.

Other drugs that block the estrogen receptor, including fulvestrant (Faslodex®) and a group of drugs called aromatase inhibitors, have been shown to be effective in treating postmenopausal women. (See information about aromatase inhibitors under Breast Cancer.) Some reports suggest that these drugs may also work in men with breast cancer. However, more studies are needed to establish their efficacy in men.

Targeted Therapies

Researchers are developing drugs that work by targeting specific molecules involved in breast cancer development. For example, some breast cancer cells overproduce the protein HER2/neu, leading to more aggressive tumors. Trastuzumab (Herceptin®) and lapatinib (Tykerb®) are drugs that target and inactivate the HER2/neu protein. They are usually given in combination with other systemic therapies.