Hormonal therapy

About 90 percent of male tumors have estrogen receptors (are ER+), meaning that they grow in response to this female hormone. 

The advantage is that they can be treated with Tamoxifen, a highly effective anti-cancer drug that targets estrogen receptors by binding and blocking them from responding to the estrogen in the blood.  
This will stop the tumor growth. Fulvestrant (Faslodex®) is another drug that also blocks estrogen receptors.
Aromatase inhibitors are a group of drugs that are effective in treating breast cancer on post-menopause women by reducing estrogen production by tissues.
Although some research suggests that they are also effective for male breast cancer, more work is necessary to prove it.

In men, in addition to anti-estrogen drugs, anti-androgen drugs can also be used to treat ER+ breast cancer.

How come? 

• Tumor cells, in addition to estrogen receptors, also have androgen receptors that once activated trigger cellular division and multiplication;
• Androgens can also be converted into estrogen in some organs – for example fat cells – increasing their concentration in the blood.

There are different strategies to interfere with androgen effects on the tumor:

• Medication, such as Leuprolide (Lupron ®) or goserelin (Zoladex ®), act on the pituitary gland to reduce testicular androgen production (as androgen is a male sex hormone);
• Anti-androgen drugs target androgen receptors in the breast cells – this includes breast cancer cells – blocking them from responding to this hormone;
• Orchiectomy, a surgical procedure in which one or both testicles are removed, decreases testosterone and different androgens levels in the blood.

These treatments are often effective as neo-adjuvant therapies – those used before surgery to reduce the size of the tumor.

Hormonal treatment can also be used to further the positive effects of other therapies.