Understanding male breast cancer

Prof Carol-Ann Benn unpacks male breast cancer.

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World stats of male breast cancer

The occurrence of male breast cancer varies throughout the world. In the UK, the incidence is approximately 0,7% of all breast cancers. In North America, there seems to be an increasing incidence, especially amongst black males. Approximately 2 190 men were diagnosed in the USA in 2010; 410 men will die from it.

Breast cancer is most commonly found in men over sixty, although men of all ages can be affected. It appears from studies, in other parts of Africa as well as South Africa, that it’s more common amongst African males (incidence of 1 – 3%).

Risk factors

It’s difficult to establish definite risk factors for breast cancer in males. Remember that 60% of women getting breast cancer have no risk factors. There is often discussion as to its relationship with gynecomastia (enlarged breast tissue in men), due to the association with possible higher levels of oestrogen. 

There is a proven relationship between obesity and male breast cancer, which is thought to increase the risk from 1 to 5 times. This is due to the elevated levels of circulating oestrogen associated with obesity. 

A link has also been found with males with a previous history of prostate cancer due to the type of medication used. The link to patients with prostate cancer may be due to a common underlying genetic mutation (BRCA 2).

There is also a link with those undergoing gender re-assignment, though the data is not well-substantiated. 

Genetic component

There does appear to be a genetic component in male breast cancer in about 4 – 40% of cases. Male breast cancer is 3 to 5 times more common in men who have had at least one first-degree female relative with breast cancer. 

Several genes have been associated in male breast cancer prevalence, including BRCA2, AR gene, cytochrome P45017 (CYP17), XXY karyotype (Klinefelter syndrome), PTEN tumour suppressor gene associated with Cowden syndrome, and CHEK2 gene. The most conclusive of these is BRCA 2, XXY and Cowden syndrome.

Male carriers of the BRCA2 mutation have an estimated 6,3% cumulative lifetime risk of breast cancer by 70 years. It’s most commonly found in Ashkenazi Jews and some Eastern Europeans populations. 

Patients with Klinefelter syndrome have a specific body shape (tall, skinny, little hair, poor coordination and reading difficulties), high oestrogen to androgen ration despite low to normal oestrogen levels. Klinefelter syndrome patients have an increased risk of breast cancer 20 times that of the risk of a normal male.

Personality of male breast cancers

The personality of male breast cancers (see It is not about size, it’s about personality) is the same as female breast cancers. 

They are most commonly ductal carcinomas and whilst lobular carcinoma is rarely seen in men, they can be associated with Kleinfelter syndrome. Any variation of ductal carcinoma can be seen in male breast cancers, including Paget’s disease (cancerous eczema of the nipple). 

Most male breast cancers (80 to 90%) are oestrogen and progesterone receptor positive and usually with a Ki-67 above 15% – luminal B.

Males usually present with advanced stage

Like female breast cancer, most male breast cancers present as a painless lump. Though, men usually present with advanced stage, due to lack of knowledge and screening amongst male patients. The myth that men can’t get breast cancer along with the lack of emphasis on male self-breast examinations contribute towards late stage diagnosis. Another reason is because men don’t have lots of breast tissue, unless they have big ‘moobs’. The ratio of male breast cancer to the male breast means that more often the breast cancer is involving the skin or underlying muscle. This commonly means  more T4 (tumours involving skin or muscle) are seen. This is relevant to the need for radiation, but remember personality not size.

Patients may also have a nipple discharge or nipple changes, and very few present with a painful swelling. 

Any one-sided breast mass that is firm, fixed or ulcerated in a man should raise suspicion. 

Investigation – triple assessment

All potential breast cancers are investigated the same way, whether in men or women. This is with the triple assessment: a good history, followed by an examination and then a mammogram and sonar (yes, you can mammogram a male ‘moob’), followed by an image-guided core needle biopsy to provide the diagnosis (no surgical biopsies please). A sonar is particularly useful in males because of the little breast tissue and to check axillary lymph nodes.

Treatment

The treatment for male breast cancer is the same as in female breast cancer and is always based around multi-disciplinary care. 

Clearly in men, breast-saving surgery is more difficult. Near impossible, but it’s determined by the size of the ‘moob’. So, most men get a mastectomy and sentinel lymph node biopsy, or axillary sampling, depending on whether glands are involved.

Chemotherapy and radiation treatment are given depending on stage and cancer biology. But as most male breast cancer presents in a locally advanced condition, they almost always require radiation and sometimes chemotherapy.

Chemotherapy today is often given based on the behaviour and personality of the cancer and not size. So, each patient will be discussed in a multi-disciplinary unit. 

In fact, some studies say that unlike in female breast cancer where radiation is required if the tumour size is greater than 5cm, in men tumour size greater than 2cm requires radiation. 

Risk of local recurrence may be high, due to the small size of the male breast and the lack of radiation given. Risk of systemic recurrence (cancer coming back elsewhere in the body) can be significantly decreased using hormonal therapy if the tumour is hormone sensitive. In the past chemical castration, or orchidectomy (removal of testicles), was used. Eekk! Thankfully, this is not done today. 

Prognosis 

There is a perception of worse prognosis in male breast cancer. 

This is not due to inherently aggressive disease but may rather be due to the later stage of presentation at diagnosis. Typically, 5 – 10% of patients will have metastatic disease (cancer spread to body) at first presentation. A study, in Scandinavia, found that men had poorer survival due to later onset and advanced stage. However, when age, stage and treatment were controlled, men actually had an inherent survival advantage.

A lovely study, in our unit, showed that men don’t like to walk around with mastectomy scars and feel shy with their tops off if they have had a breast cancer operation. Please guys, know that we can reconstruct male breasts too.