Medication for Male Breast Cancer

Although the hormones estrogen and progesterone are often associated with women, they are found in men as well. Both hormones can fuel breast cancer growth.

Men who have tumors that test positive for estrogen receptors, progesterone receptors, or both are often candidates for hormone therapy. Many older men with breast cancer have an estrogen-receptor positive or progesterone-receptor positive tumor, for reasons that are not entirely understood. Hormone receptor-positive status may be related to the aging process.

Doctors usually prescribe hormone therapy after surgery and radiation therapy are complete to destroy any remaining cancer cells and help prevent cancer from returning. Sometimes, hormone therapy is given to shrink tumors, making surgery an option. Hormone therapy can also be given to prevent cancer from developing in the other breast.

Selective Estrogen Receptor Modulators

Selective estrogen receptor modulators block the potentially harmful effects of the hormone estrogen in the breasts but allow it to function in other areas of the body, where it has a beneficial effect. For example, estrogen can help maintain bone mass in men.

One of the most commonly used medications in this class is tamoxifen. Doctors may prescribe it to prevent cancer from returning after surgery or radiation therapy in men with early breast cancer. Tamoxifen tends to work for cancers that are estrogen-receptor positive, progesterone-receptor positive, or both.

Tamoxifen is given by mouth on a daily basis after surgery or radiation therapy. Men may take the drug for as long as 5 to 10 years.

Tamoxifen may be used as the only treatment in men who have breast cancer that has spread throughout the body to help shrink or slow the growth of tumors.

Luteinizing Hormone-Releasing Hormone Agonists

Medications called luteinizing hormone-releasing hormone agonists may be prescribed to help block the production of testosterone, which can fuel breast cancer growth.

These medications stop the pituitary gland—a pea-sized gland located at the base of the brain—from producing a substance called luteinizing hormone. This hormone normally stimulates the testicles to produce testosterone. Blocking luteinizing hormone reduces the production of testosterone in men. This, in turn, helps to eliminate remaining cancer cells and reduces the chances of a recurrence.

These medications are given as shots once a month or every few months. Your doctors can determine a schedule that is right for you.

While most men with breast cancer have HER2-negative tumors, those who have HER2-positive cancer may be prescribed a drug called trastuzumab. HER2 stands for human epidermal growth factor receptor-2, a protein that encourages breast cancer cells to grow. This targeted drug destroys cancer cells while sparing healthy tissue.

Trastuzumab is a monoclonal antibody. Antibodies are immune system proteins that recognize harmful substances as foreign and help to remove them. Monoclonal antibodies bind to receptors, or proteins, on breast cancer cells. The drug trastuzumab binds to HER2, preventing tumor cells from receiving signals that tell them to multiply.

The drug may be given alone through a vein with intravenous (IV) infusion every one to three weeks for one year in men with early cancer. To manage advanced breast cancer, doctors may prescribe trastuzumab along with chemotherapy drugs.

If you have triple negative breast cancer—meaning the tumor is estrogen-receptor negative, progesterone-receptor negative, and HER2 negative—NYU Langone doctors may prescribe chemotherapy, a group of drugs that destroy cancer cells throughout the body.

Doctors also sometimes prescribe chemotherapy drugs to men who have cancer in the lymph nodes or tumors that have spread to other parts of the body, such as the liver or lungs.

Chemotherapy is usually given after surgery and radiation therapy are complete. Doctors often prescribe a combination of chemotherapy drugs to manage breast cancer. They may be given through a vein with IV infusion or by mouth. Your doctor determines the treatment schedule.

Generally, IV chemotherapy drugs are administered for several hours at a time every two to three weeks. Giving the treatment in cycles allows the body to recover between sessions. A treatment cycle may be repeated several times over a period of three to six months.

Breast cancer medications have many side effects. Chemotherapy can cause nausea, diarrhea, mouth sores, and fatigue. Hormone therapies can cause hot flashes and night sweats. Some targeted drugs can result in nausea, fatigue, fever, and skin rash.

Your doctors can help you to manage these side effects by changing the dose, prescribing other medications, or referring you to NYU Langone’s integrative health services. Most of these side effects subside after treatment is complete.

Men with breast cancer are encouraged to enroll in a clinical trial at NYU Langone, in which promising new therapies are studied. You and your doctor can discuss whether a clinical trial is right for you.

Men with estrogen-receptor positive breast cancer that has spread throughout the body may be eligible for a study of a targeted drug that blocks enzymes that contribute to breast cancer growth. The drug is taken by mouth and may be combined with hormone therapy to destroy cancer cells.

Researchers are also studying targeted drugs in combination with chemotherapy in men and women with HER2-positive breast cancer that has spread.