Male Breast Cancer

Male breast cancer remains under diagnosed and due to delays in diagnosis is often also under treated. The investigation and management of male breast cancer is based on studies on female patients. At present there is a need for further research into male breast cancer.

Also see article on Gynaecomastia.

• A rare disease (less than 300 cases diagnosed per year).¹ Male breast cancer is diagnosed in 1% of cases of male breast enlargement.²
• Unimodal distribution in men (bimodal in women).
• Peak age for presentation > 60 years.
• Europe - prevalence of 1 in 100,000 (<1% of all breast cancer is in men).³ Mortality has remained static.
• Wide variation in incidence, for example, high rates in Zambia (thought to be related to hyperoestrogenism from endemic liver infections).
• Lower incidence is seen in Japan (for both men and women).³
• Incidence rates are rising, which may actually be a reflection of increasing age of the population.

1. Increasing age.
2. Genetics.
   • Up to one fifth of men with breast cancer have a first degree relative similarly affected.
   • More commonly associated with BRCA2 mutations.¹
   • High risk groups include sub-Saharan Africa and Ashkenazi Jews.²
3. Lifestyle.
   • Certain environments e.g. furnace work, exposure to radiation and possibly electromagnetic fields.²
   • Polycyclic aromatic hydrocarbons (as in petrol and exhaust fumes).
4. Hyperoestrogenism.
   • Exogenous oestrogen.
   • Klinefelter's syndrome (47XYY) - low testosterone and increased gonadotrophins. Breast cancer is up to 50 times more frequent in this group.^1,4
   • Obesity.
   • Chronic liver conditions.
   • Pituitary adenomas leading to hyperprolactinaemia (associated with bilateral breast cancer).
   • Gynaecomastia does not lead to an increased risk.
5. Alcohol consumption.
6. Chest irradiation.

Symptoms

• Painless lump
• Pain (rarely)
• Nipple inversion or discharge⁴
• Skin changes e.g. ulceration
• Gynaecomastia - very rarely (see box below)

Signs

• Skin change
• Palpable mass
• Palpable lymph nodes

• 90% Invasive ductal¹
• 10% Ductal carcinoma in situ
• Others e.g. medullary, mucinous and Paget's

Majority of tumours are grade III in men at time of presentation.

It is estimated that more than 90% of male breast cancer is oestrogen receptor positive, and even higher values are progesterone receptor positive. Male breast cancer tissue may also be positive for androgen receptors (although, values reported vary widely).

1. Clinical: based on history and examination.
2. Imaging: mammography (sensitivity 92% and specificity 90%) / ultrasonography.^3,4
3. Tissue: FNAC or biopsy (core or open). Biopsy is preferred as malignant cells on FNAC may be a ductal carcinoma in situ rather than more invasive disease.

1. Surgery: wide local excision or mastectomy (more common in men as paucity of breast tissue and nipple usually removed). This may be associated with axillary lymph node sampling and clearance. Sentinel node biopsy is being used in clinically node-negative disease. May need skin flap or nipple reconstruction.^3,4,5
2. Radiotherapy: adjuvant local radiotherapy or post-mastectomy. Regional lymph nodes may also be treated with radiotherapy.
3. Adjuvant hormone therapy: tamoxifen is used (as in women) and improves survival.^2,4
4. Chemotherapy: regimens using cyclophosphamide, methotrexate, 5-fluorouracil and taxanes have been used with improved survival rates. The role of taxanes however, remains to be elucidated.
5. Trastuzumab is used when more adverse features are present as in women (see article on trastuzumab).² However, there is currently no information on the benefits of trastuzumab in male breast cancer.³
6. Metastatic or more advanced disease: hormonal therapies are the main treatments used. Chemotherapy has been used as a second line (and for palliative purposes also).^6,7
7. Other therapies that have been used:^3,4
   • Gonadal ablation in metastatic male breast cancer
   • Orchidectomy
   • Adrenalectomy
   • Hypophysectomy
   • Adjuvant aromatase inhibitors e.g. anastrozole

There is often a delay in diagnosis of male breast cancer, thus prognosis at presentation is worse in comparison to women.

• 5 year survival depends on the stage of the disease (75-100% for stage I diseases and 30-60% for stage III disease).⁴
• The presence of carcinoma in the other breast is also increased.⁷