Management of Male Breast Cancer

Axillary and Radiation Therapy

For patients with clinically node-negative axilla, sentinel lymph node biopsy (SLNB) is the recommended approach for axillary staging. If the cancer has spread to the lymph nodes, more extensive axillary surgery may be required.

Following surgery, the indications for radiation therapy (RT) are identical to those used in female breast cancer patients. This may include whole-breast irradiation following BCS or post-mastectomy radiation therapy (PMRT) in specific high-risk scenarios.

Systemic Therapy and Molecular Assays

Systemic therapy is tailored to the molecular subtype of the tumor, following established female-based guidelines for chemotherapy and HER2-targeted therapy.

Molecular Profiling

While data specifically for males are limited, the use of molecular assays can provide significant prognostic value. Specifically, the 21-gene assay recurrence score is suggested to offer useful prognostic information to guide treatment decisions.

Adjuvant Endocrine Therapy

For hormone receptor (HR)-positive disease, endocrine therapy is a cornerstone of adjuvant treatment. The preferred option is tamoxifen, typically administered for 5–10 years.

A critical distinction in male management involves the use of aromatase inhibitors. If tamoxifen is contraindicated, a GnRH analog combined with an aromatase inhibitor is recommended.

Clinical Pearl: Single-agent aromatase inhibitor therapy is not recommended for males. Because males rely on the peripheral conversion of androgens to estrogens via the aromatase enzyme, inhibiting this enzyme without suppressing the primary source of androgens (via GnRH analogs) results in inadequate estradiol suppression and inferior clinical outcomes.

Management of Advanced Disease

For patients with advanced or metastatic disease, management mirrors female protocols. This includes:

• Endocrine-based regimens: If an aromatase inhibitor is used, it must be given concurrently with a GnRH analog.
• Targeted Therapies: While specific male clinical trials are lacking, real-world data suggest that agents such as CDK4/6 inhibitors, mTOR inhibitors, and PIK3CA inhibitors show comparable efficacy to those seen in females, making their use a reasonable clinical choice.
• Other Agents: Other options may include fulvestrant, immunotherapy, or PARP inhibitors depending on the specific molecular profile and disease stage.

Long-term Surveillance and Follow-up

Survivorship care for males requires specific monitoring, particularly when intensive endocrine modulation is used. For patients receiving adjuvant GnRH analog therapy, it is mandatory to perform a bone density assessment at baseline and every 2 years to manage the risk of bone loss associated with prolonged estrogen suppression.