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ASCO Issues Guidelines on Managing Male Breast Cancer

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For men diagnosed with breast cancer, decisions about using hormonal therapy, targeted therapy, and immunotherapy medicines after surgery should be made the same way they are for women diagnosed with breast cancer, according to guidelines on managing male breast cancer released by the American Society of Clinical Oncology (ASCO).

The guidelines were published online on Feb. 24, 2020, by the journal JCO Oncology Practice. Read “Management of Male Breast Cancer: ASCO Guideline Summary.”

ASCO is a national organization of oncologists and other cancer care providers. ASCO guidelines give doctors recommendations for treatments and testing that are supported by much credible research and experience.

Male breast cancer

While breast cancer in men is rare, it does happen. Fewer than 1% of all breast cancers are diagnosed in men. In 2019, about 2,670 new cases of invasive breast cancer were diagnosed in men. For men, the lifetime risk of getting breast cancer is about 1 in 833.

Like breast cancer in women, breast cancer in men can be hormone-receptor-positive or hormone-receptor-negative, as well as HER2-positive or HER2-negative.

Because the number of cases of breast cancer in men is relatively small compared to the number of cases in women, there is a lack of information on male breast cancer in general, and there have been no studies focused specifically on treatments for male breast cancer.

To help men diagnosed with breast cancer and their doctors make decisions about treatments, ASCO put out guidelines on how to manage male breast cancer and also called for clinical studies looking at treatments specifically for male breast cancer.

Guideline recommendations

The guidelines recommend:

  • Men diagnosed with hormone-receptor-positive breast cancer who would benefit from hormonal therapy after surgery should be offered tamoxifen.
  • Men diagnosed with hormone-receptor-positive breast cancer who would benefit from hormonal therapy after surgery but aren’t good candidates to take tamoxifen may be offered an aromatase inhibitor and a gonadotropin-releasing hormone (GnRH) agonist. In men, GnRH agonists such as Zoladex (chemical name: goserelin) cause the testicles to stop making testosterone.
  • Men who are treated with hormonal therapy after surgery initially should take the hormonal therapy for 5 years.
  • Men who have completed 5 years of tamoxifen and still have a high risk of breast cancer recurrence may be offered another 5 years of tamoxifen — for a total of 10 years of tamoxifen.
  • Men diagnosed with early-stage breast cancer should not be treated with bone-strengthening medicines to reduce the risk of recurrence. Men diagnosed with early-stage disease may take bone-strengthening medicines to prevent or treat osteoporosis.
  • Men diagnosed with advanced-stage or metastatic hormone-receptor-positive, HER2-negative breast cancer should be offered hormonal therapy as the first treatment for the disease, unless the person has severe organ dysfunction or rapidly growing disease. Options include tamoxifen, an aromatase inhibitor with a GnRH agonist, and Faslodex (chemical name: fulvestrant). CDK4/6 inhibitors can be used in men as they are used in women.
  • Men diagnosed with recurrent metastatic hormone-receptor-positive, HER2-negative breast cancer while being treated with hormonal therapy after surgery should be offered a different hormonal therapy medicine, unless the person has severe organ dysfunction or rapidly growing disease.
  • Hormonal therapy for men diagnosed with advanced-stage or metastatic hormone-receptor-positive, HER2-negative breast cancer may be given in the same sequence as it is in women.
  • Targeted therapy medicines that target the HER2 or PIK3CA genes, PD-L1 proteins, or mutations in the BRCA1 or BRCA2 genes may be used to treat advanced-stage or metastatic male breast cancer in the same way they are used to treat breast cancer in women.
  • The side effects of hormonal therapy — including joint pain, hot flashes, and blood clots — in men should be managed the same way they are in women.
  • Men diagnosed with breast cancer should not take testosterone or androgen supplements.
  • Doctors should talk to men who have been diagnosed with breast cancer about the symptoms of recurrence. Men diagnosed with breast cancer should have a survivorship care plan, and the plan should include exams by a doctor who has experience monitoring people who have been diagnosed with breast cancer.
  • An annual mammogram of the breast where the cancer was should be offered to men who were treated with lumpectomy.
  • An annual mammogram of both breasts may be offered to men with a history of breast cancer who have a genetic mutation linked to a higher risk of the disease.
  • Routine breast MRI is not recommended for men who have been diagnosed with breast cancer.
  • Men diagnosed with breast cancer should be offered genetic counseling and genetic testing for mutations linked to a higher risk of the disease.

What this means for you

Even though breast cancer in men is rare and no research has been done specifically on male breast cancer, it’s important that men be aware of any signs that might indicate breast cancer.

Talk to your doctor right away about any changes in your breasts, including:

  • nipple pain
  • inverted nipple
  • nipple discharge
  • sores on the nipple and/or areola area
  • enlarged lymph nodes under the arm

Because many men don’t consider the possibility that they may develop breast cancer, they may wait a year or longer to talk to their doctor after noticing a breast symptom. This means the cancer is diagnosed at a later stage.

If you’re a man who has been diagnosed with breast cancer, these ASCO guidelines can help you and your doctor make the best treatment decisions for your unique situation.

For more information, visit the Breastcancer.org pages on Male Breast Cancer.

If you're a man who has been diagnosed with breast cancer and would like to talk with others, join the Breastcancer.org Discussion Board forum Male Breast Cancer.

Written by: Jamie DePolo, senior editor

Reviewed by: Brian Wojciechowski, M.D., medical adviser


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