Breast Cancer in Men

Overview of Male Breast Cancer

The
etiology, diagnosis, and treatment of breast cancer in males is similar
to that in females. Unlike breast cancer in females, however, breast
cancer in men is rare. Although its frequency has increased in recent
decades—particularly in the urban United States, Canada, and the United
Kingdom—breast cancer in males accounts for less than 1% of breast
cancers.^[3] In
the United States, males were expected to account for only 1,970 of the
estimated 209,060 cases of breast cancer that were predicted to occur
in 2010.^{[1, 2]} Unfortunately,
this rarity has largely precluded prospective randomized clinical
trials. It may also contribute to the infrequency of early diagnosis.
Men tend to be diagnosed with breast cancer at an older age than women,
and they have proportionately higher mortality, although outcomes for
male and female patients with breast cancer are similar when survival is
adjusted for age at diagnosis and stage of disease.^[1] For more information, see Breast Cancer, as well as Breast Cancer Screening, Breast Cancer Histology, Adjuvant Therapy in Breast Cancer, and Surgical Treatment of Breast Cancer.
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Etiology

Environmental
and genetic risk factors for male breast cancer have been identified.
In approximately 30% of cases, the family history is positive for breast
cancer. A familial form of breast cancer is seen in which both sexes
are at increased risk for breast cancer. Familial cases usually have BRCA2 rather than BRCA1 mutations.^[1] Klinefelter syndrome is the strongest risk factor.^[1] Males with the syndrome have a risk of breast cancer that approaches that of females. Exogenous
hormone therapy, such as treatment for prostate cancer, is not
associated with an increased risk of male breast tumors; breast masses
in these patients are more commonly found to be metastatic disease
rather than primary breast cancer. However, an increased risk of breast
tumors was found in men exposed to estrogen-containing creams in the
soap and perfume industries, as well as in men with testicular injury.
Liver cirrhosis, which may be associated with elevated estrogen levels,
has been associated with male breast cancer. A few transsexual
(male to female) patients have been reported with breast cancer 5-10
years after initiation of estrogen therapy; however, it is not known
whether these patients are at an increased risk compared with
nontranssexual males.^[3] These
epidemiologic factors, in addition to studies suggesting that men with
breast cancer have elevated estriol production, indicate a relationship
between male breast cancer and hormones.
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Diagnosis

Male
breast cancer usually presents as a painless lump. In 75% of cases, the
lump is a hard and fixed nodule in the subareolar region, with nipple
commitment earlier than in women.^[7] Often,
the disease is not detected until late in its course: more than 40% of
patients have stage III or IV disease at diagnosis.^[1] In patients with clinical features completely consistent with gynecomastia,
breast cancer may be excluded on clinical grounds, and no further
evaluation may be necessary. If findings are equivocal, however,
mammography can be useful in diagnosis.^[3] See Male Breast Cancer Imaging for further information on this topic. Fine-needle aspiration biopsy can confirm the diagnosis.^[4] Histologically,
the majority of breast cancers in men are infiltrating ductal
carcinomas, but the entire spectrum of histological variants of breast
cancer has been seen. Papillary carcinoma is a distant second in
frequency. Lobular carcinoma is uncommon.^[3]
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Treatment & Management

The
standard of care for male breast cancer is modified radical mastectomy
with sentinel node biopsy. Approximately 90% of these tumors are
hormone-receptor positive; consequently, tamoxifen is the standard
choice for adjuvant chemotherapy.^[1] Indications for radiotherapy are similar to those for female breast cancer (see Breast Cancer, as well as Breast Cancer Screening, Breast Cancer Histology, Adjuvant Therapy in Breast Cancer, and Surgical Treatment of Breast Cancer). Hormone
therapy is the principal treatment for metastatic disease. However,
chemotherapy can also provide palliation. Second-line hormonal
approaches include orchiectomy, aromatase inhibitors, and androgen
ablation.^[6]
Long-term monitoring

Men
who have had breast cancer are at increased risk for a second
ipsilateral or contralateral breast cancer. The risk of subsequent
contralateral breast cancer is highest in men who were younger than 50
years when their initial cancer was diagnosed. Thus, periodic screening
is probably advisable.^[5]