Known risk factors include radiation exposure, exposure to female hormones (estrogen), and genetic factors. High estrogen exposure may occur by medications, obesity, or liver disease, and genetic links include a high prevalence of female breast cancer in close relatives. Chronic alcoholism has been linked to male breast cancer. The highest risk for male breast cancer is carried by men with Klinefelter syndrome. Male BRCA mutation carriers are thought to be at higher risk for breast cancer.
Pathology
As in females, infiltrating ductal carcinoma is the most common type. While intraductal cancer, inflammatory carcinoma, and Paget's disease of the nipple have been described, lobular carcinoma in situ has not been seen in men. Breast cancer in men spreads via lymphatics and blood stream like female breast cancer. Accordingly, the TNM staging system for breast cancer is the same for men and women.
Women's breasts when mature are composed of a nipple and areola, behind which are the ducts and lobes, nested within fatty tissue (stroma). Men's breasts also have a nipple, areola, and ducts, but few lobes (for milk) and usually scant fatty tissue. During a woman's lifetime, her breast tissue is exposed to constant washings of female hormones, which promote growth. Hormonal growth, coupled with a greater amount of breast tissue, accounts for the greater incidence of breast cancer in women. Other factors that increase a woman's risk include having a gene for breast cancer, and environmental exposure to estrogens. Size of the lesion and lymph node involvement determine prognosis; thus small lesions without lymph node involvement have the best prognosis. Estrogen receptor and progesterone receptor status and HER2/neu gene amplification need to be reported as they may affect treatment options. About 85% of all male breast cancers are estrogen receptor–positive, and 70% are progesterone receptor–positive.
Typically self-examination leads to the detection of a lump in the breast which requires further investigation. Other less common symptoms include nipple discharge, nipple retraction. swelling of the breast, or a skin lesion such as an ulcer. Ultrasound and mammography may be used for its further definition. The lump can be examined either by a needle biopsy where a thin needle is placed into the lump to extract some tissue or by an excisional biopsy where under local anesthesia a small skin cut is made and the lump is removed. Not all palpable lesions in the male breast are cancerous, for instance a biopsy may reveal a benign fibroadenoma. In a larger study from Finland the average size of a male breast cancer lesion was 1.8 cm. Beside the histologic examination estrogen and progesterone receptor studies are performed. Further, the HER2 test is used to check for a growth factor protein. Its activity can be increased in active cancer cells and helps determine if monoclonal antibody therapy (i.e. Trastuzumab) may be useful.
Male breast cancer can recur locally after therapy, or can become metastatic.
Staging
In addition to TNM staging surgical staging for breast cancer is used; it is the same as in female breast cancer and facilitates treatment and analysis.
1.) Stage I refers to invasive breast cancer with the tumor not exceeding 2 cm and absence of lymph node involvement.
2.) Stage II: Includes stages IIA and IIB
Stage IIA: One of the following applies:
T0 or T1, N1 (but not N1mi), M0: The tumor is 2 cm or less across (or is not found) (T1 or T0) and either:
It has spread to 1 to 3 axillary lymph nodes (N1a), but not to distant sites (M0), OR Tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy (N1b), but not in distant sites (M0), OR. It has spread to 1 to 3 axillary lymph nodes, and tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy (N1c), but not to distant sites (M0). OR
T2, N0, M0: The tumor is larger than 2 cm across and less than 5 cm (T2), but it hasn't spread to the lymph nodes (N0) or to distant sites (M0). Stage IIB: One of the following applies: T2, N1, M0: The tumor is larger than 2 cm and less than 5 cm across (T2). It has spread to 1 to 3 axillary lymph nodes and/or tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy (N1). It has not spread to distant sites (M0). OR T3, N0, M0: The tumor is larger than 5 cm across but does not grow into the chest wall or skin (T3). It has not spread to lymph nodes (N0) or to distant sites (M0).
3.) Stage III is divided into three subcategories:
- In IIIA there is breast cancer with axillary lymph nodes clumped together or attached to other structures.
- In IIIB the tumor has spread to the chestwall or skin, and may have involved lymph nodes of the axilla and/or breastbone.
- In IIIC the tumor has spread to the chest wall or skin and lymph nodes below or above the collar bone are affected.
4.) Stage IV is applied to metastatic breast cancer; typically lungs, liver, bone, or brain are involved.
There are some conditions when the Breast Cancer increase the risk, such as:
Gynecomastia
If a man has an increase in breast tissue, or can feel a small amount of tissue about the shape of a button just beneath his areola, it may be a condition called gynecomastia. This is caused by hormonal imbalances, obesity, habitual use of marijuana, severe liver dysfunction, or could be a side effect of some medications. Gynecomastia is not thought to increase a man's risk of breast cancer.
Klinefelter Syndrome
Klinefelter syndrome is a rare genetic problem, which could indicate an increased risk of male breast cancer. In Klinefelter syndrome, a man has an extra X chromosome, may have smaller testicles, enlarged breasts and may be infertile.
Family History or Genetic Mutation
Men who have a family history of male or female breast cancer, or who carry the mutated BRCA1 or BRCA2 gene are at increased risk of developing breast cancer. Knowing your family health history or your genetic risk helps you and your doctor be aware of your risk level.
Common Male Breast Cancer Diagnoses:
Men who are diagnosed with male breast cancer are literally one in a thousand. The American Cancer Society reports that a man faces a lifetime risk of 1/10th of 1%, and has the same survival rates as a woman. Here are the most common diagnoses for male breast cancer:
IDC or Infiltrating (or invasive) Ductal Carcinoma
Invasive ductal carcinoma is the most common form of male breast cancer, ranking at 80 to 90 percent of all men's breast cancer diagnoses. IDC originates in the duct and breaks into, or invades, the surrounding fatty tissue. It may be contained only within the breast, or it can metasticize (spread) to other parts of the body.
LBC (Lobular Breast Cancer)
Since most men do not have any lobes in their breast tissue, this kind of breast cancer is extremely rare in men. It occurs at the rate of two percent of all ductal or lobular male breast cancers.
Paget's Disease of the Nipple
This cancer can start inside the nipple or under the areola, and then break through the overlying skin. Paget's disease would appear similar to a rash, but will not respond to the standard skin rash treatments. It is possible that a lump may also be associated with Paget's disease, whether the patient is male or female.
Treatment largely follows patterns that have been set for the management of postmenopausal breast cancer. The initial treatment is surgical and consists of a modified radical mastectomy with axillary dissection or lumpectomy and radiation therapy with similar treatment results as in women. Also, mastectomy with sentinel lymph node biopsy is a treatment option. In men with node-negative tumors, adjuvant therapy is applied under the same considerations as in women with node-negative breast cancer. Similarly, with node-positive tumors, men increase survival using the same adjuvants as affected women, namely both chemotherapy plus tamoxifen and other hormonal therapy. There are no controlled studies in men comparing adjuvant options. In the vast majority of men with breast cancer hormone receptor studies are positive, and those situations are typically treated with hormonal therapy.
Locally recurrent disease is treated with surgical excision or radiation therapy combined with chemotherapy. Distant metastases are treated with hormonal therapy, chemotherapy, or a combination of both. Bones can be affected either by metastasis or weakened from hormonal therapy; bisphosphonates may be used to counterbalance this process and strengthen bones.
Adjusted for age and stage the prognosis for breast cancer in men is similar to that in women. Prognostically favorable are smaller tumor size and absence or paucity of local lymph node involvement. Hormonal treatment may be associated with hot flashes and impotence.
