Men's Health: Shining a Light on Male Breast Cancer

We start Movember, from where we left off in October with a look at breast cancer, this time in men. Although male breast cancer is rare, it is no-less of a shock and worry for the men and their families who are affected by it.

Currently, over 300 men are diagnosed with breast cancer in the UK each year, with between 15 and 20 of these cases occurring in Wales. However, evidence suggests that the incidence of male breast cancer is on the rise across most parts of the world, for several different reasons.

Survival rates for male breast cancer are good and exceed 80%. Although since male breast cancer is rare, breast cancers when diagnosed tend to be more advanced, with greater involvement of lymph nodes and higher prevalence of metastasis at the time of diagnosis. However, survival data indicate that outcomes for male breast cancer are like that for women, when tumours of the same stage are compared.

The incidence of breast cancer in males increases with age and peaks in the six and early seventh decade. Breast cancer in women on the other hand, displays two peaks one between the ages of 50 and 54 – possibly reflecting the start of screening and increased detection – and the second between the ages of 65-69.

Symptoms of male breast cancer include nipple retraction, red or flaky skin on the breast and around the nipple, palpable mass or lump in the breast, irritation or dimpling of the breast skin and discharge from the nipple.

Like breast cancer in women, family history and presence of susceptibility genes such as mutations in the BRAC1/2 genes increases the risk of breast cancer in males. Other risk factors also include cirrhosis of the liver - which lowers the levels of circulating male hormones, called androgens, while raising the level of oestrogen -obesity, prior radiation exposure to the chest, undescended testis, and mumps orchitis, where the virus causes painful swelling and damage to one of the testicles.

Klinefelter syndrome, a rare genetic condition where the male inherits an extra copy of the female X chromosome is also associated with male breast cancer as an imbalance of female and male sex hormones may result from the body producing more oestrogen and lower levels of androgens.

Male breast cancer is often treated in the same way as female breast cancer using a combination of surgery, radiotherapy, chemotherapy, and targeted therapies depending on the size of the tumour and the stage of the disease at diagnosis.

Most male breast cancers are oestrogen receptor positive, whereas HER2 (the biological target of Herceptin) and triple negative breast cancer, are rarely reported. The presence of an oestrogen receptor which drives the growth of breast tumours permits male breast cancer patients to be treated with standard hormone therapy in the same way as for women.

Tamoxifen which prevents the binding of oestrogen to its receptor on the surface of breast cancer cells is usually the most common hormone therapy used. Men often take the drug for up to five years, sometimes this timeframe is extended if the therapy is well tolerated, and side-effects are few.

Aromatase inhibitors which stop the conversion of male hormones (called androgens) to oestrogen are sometimes used if tamoxifen is causing unpleasant side-effects or has stopped working.

As the testicles can also directly produce oestrogen, other therapies such Zoladex® may be incorporated to block signals sent from the pituitary gland at the base of the brain, from stimulating the testicles to produce both oestrogen and testosterone.

Genetically, both female and male breast cancer are similar, although there are some gender-specific differences reported, with biological pathways present in female breast cancer that are absent in the male form, and vice-versa. Due to its rarity, clinical trials that focus solely on male breast cancer are few and far between, which highlights the need for collaborative research across countries and continents.

Cancer Research Wales remains connected with the global research community through our membership of the International Cancer Research Partnership (ICRP) and allows us to share our research across the globe, as well as bring new ideas and ways of working back home to Wales.