17-08: Carcinoma of the Male Breast

Breast cancer in men is a rare disease; the incidence is only about 1% of all breast cancer diagnoses. The average age at occurrence is about 70 years, and there may be an increased incidence of breast cancer in men with prostate cancer. As in women, hormonal influences are probably related to the development of male breast cancer. There is a high incidence of both breast cancer and gynecomastia in Bantu men, theoretically owing to failure of estrogen inactivation by associated liver disease. It is important to note that first-degree relatives of men with breast cancer are considered to be at high risk. This risk should be taken into account when discussing options with the patient and family. In addition, BRCA2 mutations are common in men with breast cancer. Men with breast cancer, especially with a history of prostate cancer, should receive genetic counseling.

A painless lump, occasionally associated with nipple discharge, retraction, erosion, or ulceration, is the primary complaint. Examination usually shows a hard, ill-defined, nontender mass beneath the nipple or areola. Gynecomastia not uncommonly precedes or accompanies breast cancer in men. Nipple discharge is an uncommon presentation for breast cancer in men but is an ominous finding associated with carcinoma in nearly 75% of cases.

Breast cancer staging is the same in men as in women. Gynecomastia and metastatic cancer from another site (eg, prostate) must be considered in the differential diagnosis. Benign tumors are rare, and biopsy should be performed on all males with a defined breast mass.

Treatment consists of modified radical mastectomy in operable patients, who should be chosen by the same criteria as women with the disease. Breast conserving therapy is rarely performed. Irradiation is the first step in treating localized metastases in the skin, lymph nodes, or skeleton that are causing symptoms. Examination of the cancer for hormone receptors and HER2 overexpression is of value in determining adjuvant therapy. Over 95% of men have ER-positive tumors and less than 10% have overexpression of HER2. Androgen receptor is also commonly overexpressed in male breast cancer. Adjuvant systemic therapy and radiation are used for the same indications as in breast cancer in women.

Because breast cancer in men is frequently hormone receptor positive, diagnosed late, and is a disseminated disease, endocrine therapy is of considerable importance in its management. Tamoxifen is the main medication for management of advanced breast cancer in men. Tamoxifen (20 mg orally daily) should be the initial treatment. There is little data regarding the use of AIs in men, but they are being used more frequently. Castration in advanced breast cancer is a successful measure and more beneficial than the same procedure in women but is rarely used. Objective evidence of regression may be seen in 60–70% of men with endocrine therapy for metastatic disease—approximately twice the proportion in women. Bone is the most frequent site of metastases from breast cancer in men (as in women), and endocrine therapy relieves bone pain in most patients so treated. The longer the interval between mastectomy and recurrence, the longer the remission following treatment is likely.

Chemotherapy should be administered for the same indications and using the same dosage schedules as for women with metastatic disease or for adjuvant treatment.

A large population-based, international breast cancer study reported that after adjustment for prognostic features (age, stage, treatment), men have a similar relative survival stage for stage compared to women. For node-positive disease, 5-year survival is approximately 69%, and for node-negative disease, it is about 88%.

For those patients whose disease progresses despite treatment, meticulous efforts at palliative care are essential (see Chapter 5).