What is correct regarding male breast cancer?

Male Breast Cancer: Key Characteristics and Management

Male breast cancer is typically hormonally dependent, with most cases being hormone receptor-positive, making tamoxifen the standard adjuvant therapy for these patients. 1

Epidemiology and Risk Factors

• Male breast cancer is rare, representing approximately 1% of all breast carcinomas diagnosed in the United States each year 2
• The average age of diagnosis for male breast cancer is 67 years, which is approximately 5 years older than for women (62 years), with incidence rates rising steadily with age 1
• Male breast cancer does NOT have a peak incidence at age 40; rather, it typically affects older men 1
• Key risk factors include:
  • Family history of breast cancer
  • Black ethnicity
  • Radiation exposure to chest
  • Genetic predisposition (BRCA2, BRCA1, CHEK2, PALB2 mutations)
  • Conditions associated with hyperestrogenism (e.g., Klinefelter's syndrome) 1, 3

Clinical Presentation

• The most common clinical presentation is a painless palpable retroareolar lump 2
• Male breast cancer does NOT typically present with bloody nipple discharge 4
• Approximately 90% of male breast tumors are invasive ductal carcinomas 2
• Due to delayed presentation, up to 40% of cases have advanced disease (stage III or IV) at diagnosis 3

Hormonal Dependence and Receptor Status

• Male breast cancer is predominantly hormone receptor-positive:
  • Approximately 81% of tumors are estrogen receptor positive
  • About 74% are progesterone receptor positive 5
• This hormonal dependence makes endocrine therapy highly effective in treatment 1, 3

Treatment Approach

Endocrine Therapy

• Tamoxifen is the standard adjuvant therapy for hormone receptor-positive male breast cancer and is NOT seldom indicated 1
• Men with hormone receptor-positive breast cancer who are candidates for adjuvant endocrine therapy should be offered tamoxifen for an initial duration of five years 1
• Men who have completed five years of tamoxifen, have tolerated therapy, and still have a high risk of recurrence may be offered an additional five years of tamoxifen therapy 1
• Aromatase inhibitors alone are less effective in men because they do not inhibit testicular estrogen production; if used due to tamoxifen contraindication, they should be combined with a gonadotropin-releasing hormone agonist/antagonist 1, 3

Advanced or Metastatic Disease

• Men with advanced or metastatic, hormone receptor-positive, HER2-negative breast cancer should be offered endocrine therapy as first-line therapy except in cases of visceral crisis or rapidly progressive disease 1
• Options include tamoxifen, an aromatase inhibitor with a gonadotropin-releasing hormone agent, and fulvestrant 1
• Cyclin-dependent kinase 4/6 inhibitors can be used in men as they are used in women 1

Special Considerations

• Testosterone/androgen supplementation should not be used by men with breast cancer 1
• Genetic counseling and germline genetic testing of cancer predisposition genes should be offered to all men with breast cancer 1
• Side effects from tamoxifen can lead to non-compliance in a substantial number of men, requiring careful monitoring and management 3

Surveillance

• Ipsilateral annual mammogram should be offered to men with a history of breast cancer treated with lumpectomy 1
• Contralateral annual mammogram may be offered to men with a history of breast cancer and a genetic predisposing mutation 1
• Breast magnetic resonance imaging is not recommended routinely 1

Male breast cancer differs from female breast cancer in some aspects, but the high rate of hormone receptor positivity makes endocrine therapy, particularly tamoxifen, a cornerstone of treatment rather than a seldom-indicated option.