ASCO Guidelines for Men with Breast Cancer

Although rare, breast cancer does occur in men. Male breast cancer makes up less than 1 percent of all breast cancers diagnosed in the United States. For men, the lifetime risk of breast cancer is about 1 in 1,000. In 2020, it is likely that about 2,620 men will be diagnosed with breast cancer and 520 men will die from the disease.^1,2

Breast cancer in both men and women can be hormone-receptor-positive or hormone-receptor negative. It can also be HER2-positive or HER2-negative.¹

There are many gaps in research and knowledge about male breast cancer and the best ways to treat and manage it. Most treatments are currently based on research done on women with breast cancer. While there are clinical trials focusing on men, many are ongoing. They also do not address the many concerns specific to male breast cancer.¹

The American Society of Clinical Oncology (ASCO) has put out guidelines for the management and treatment of male breast cancer. ASCO is a national group of oncologists and other cancer care providers. Their guidelines give doctors suggestions for treatment and managing the disease that are supported by research.²

Overall, the ASCO guidelines recommend that male breast cancer be treated and managed in the same way it is for women diagnosed with breast cancer. This includes hormone therapy, targeted therapy, and immunotherapy drugs after surgery.¹

Guidelines for men with breast cancer

The ASCO guidelines recommend¹:

• Men with hormone receptor-positive breast cancer who would benefit from hormone therapy after surgery should be offered tamoxifen. This is similar to the guidelines for women.
• Men with hormone receptor-positive breast cancer who would benefit from hormone therapy after surgery but cannot take tamoxifen may be offered a gonadotropin-releasing hormone (GnRH) agonist/antagonist and an aromatase inhibitor. A GnRH agonist can lower the levels of sex hormones produced by the testicles.
• Men who are treated with hormone therapy after surgery should take the therapy for 5 years.
• Men who have finished the 5 years of tamoxifen (or other hormone therapy) but still have a high risk of recurrence may be offered 5 more years of hormone therapy.
• Men with early-stage breast cancer should not be given bone-strengthening drugs to reduce recurrence but may take these drugs to prevent or treat osteoporosis.
• Men with advanced or metastatic hormone-receptor-positive, HER2-negative breast cancer should be offered hormone therapy as a first treatment choice. Exceptions to this include men with severe organ dysfunction or rapidly progressing disease. Options can include tamoxifen, an aromatase inhibitor with a GnRH agent, and fulvestrant (Faslodex™). Also, CDK4/6 inhibitors like palbociclib (Ibrance™) can be used in men just like they are for women.
• Men with recurrent metastatic hormone receptor-positive, HER2-negative breast cancer while being treated with hormone therapy should be offered an alternative hormone therapy treatment. Exceptions to this include men with severe organ dysfunction or rapidly progressing disease.
• Hormone therapy for men with advanced or metastatic hormone-receptor-positive, HER2-negative breast cancer may follow the same order as women’s treatment.
• Therapy drugs that target the HER2, PDL-1, PIK3CA, or BRCA1 or BRCA2 genes may be used to treat advanced or metastatic breast cancer in men in the same way they are used to treat breast cancer in women.
• Side effects of hormone therapy in men should be managed the same way they are in women. This includes side effects like joint pain, hot flashes, and blood clots.
• Men with breast cancer should not use testosterone or androgen supplements.
• Doctors should talk to men with breast cancer about the symptoms of recurrence. Men should regularly see a doctor who has experience monitoring people who have been diagnosed with breast cancer.
• Men with breast cancer who were treated with lumpectomy should be offered a yearly mammogram. The mammogram should be done on the same side as the cancer.
• For men with a history of breast cancer and a genetic predisposing mutation, contralateral (on the opposite side) should be offered.
• Even for men with a history of breast cancer, breast MRI is not recommended.
• Genetic counseling and genetic testing should be offered to men with breast cancer.

Things to consider

Though these are general guidelines, each person is different. Talk with your oncologist and treatment team about how these new guidelines will affect your treatment course and post-treatment monitoring.