Teresa G Odle. The Gale Encyclopedia of Cancer. Editor: Jacqueline L Longe. 2nd Edition, Volume 2, Gale, 2006.

Definition

Male breast cancer is a malignant tumor that forms in a man’s breast.

Description

Breast cancer is rare in men, but can be serious and fatal. Many people believe that only women can get breast cancer, but men have breast tissue that also can develop cancer. When men and women are born, they have a small amount of breast tissue with a few tubular passages called ducts located under the nipple and the area around the nipple (areola). By puberty, female sex hormones cause breast ducts to grow and milk glands to form at the ends of the ducts. But male hormones eventually prevent further breast tissue growth. Although male breast tissue still contains some ducts, it will have only a few—or no—lobules. Near the breasts of men and women are axillary lymph nodes. These are underarm small structures shaped like beans that collect cells from lymphatic vessels. Lymphatic vessels carry lymph, a clear fluid that contains fluid from tissues, cells from the immune system, and various waste products throughout the body. The axillary lymph nodes are important to breast cancer patients, as they play a role in the spread and staging of breast cancer.

Breast cancer is much more common in women, mostly because women have many more breast cells that can undergo cancerous changes and because women are exposed to the effects of female hormones.

Infiltrating ductal carcinoma is the most common type of breast cancer in men. It is a type of adenocarcinoma, or a type of cancer that occurs in glandular tissue. Infiltrating ductal carcinoma starts in a breast duct and spreads beyond the cells lining the ducts to other tissues in the breast. Once the cancer begins spreading into the breast, it can spread to other parts of the body. This distant spread is called metastasis. When breast cancer metastasizes to other areas of the body, it can cause serious, life-threatening consequences. For example, breast cancer might spread to the liver or lungs. About 80% to 90% of all male breast cancers are infiltrating ductal carcinomas.

Ductal carcinoma in situ (DCIS) is not common; it accounts for about 10% of all male breast cancers. It also is an adenocarcinoma. In situ cancers remain in the immediate area where they began, so DCIS remains confined to the breast ducts and does not spread to the fatty tissues of the breast. This means it is likely found early. DCIS also may be called intraductal carcinoma.

Other types of breast cancer are very rare in men. Adenocarcinomas that are lobular (forming in the milk glands or lobules) only occur in about 2% of male breast cancer cases because men normally do not have milk gland tissues. Inflammatory breast cancer, a serious form of breast cancer in which the breast looks red and swollen and feels warm, also occurs rarely. Paget’s disease of the nipple, a type of breast cancer that grows from the ducts beneath the nipple onto the nipple’s surface, only accounts for about 1% of female breast cancers. However, slightly more men have this form of breast cancer than women. Sometimes, Paget’s disease is associated with another form of breast cancer.

Although not a form of cancer, but a benign condition, gynecomastia is important to mention. It is the most common of all male breast disorders and can be associated with male breast cancer in a rare condition called Klilnefelter’s syndrome. Gynecomastia most often occurs in teenage boys when their hormones change during puberty. Older men also may experience the condition when their hormone balance changes as they age. Gynecomastia is an increase in the amount of breast tissue, or breast tissue enlargement. If a man has Klinefelter’s syndrome, he can develop gynecomastia and increased risk of breast cancer.

Demographics

Breast cancer in men is rare, accounting for less than 1% of all breast cancers. Still, about 1,450 American men were diagnosed with the disease and 470 men died from it in 2004. Although studies show the number of breast cancer cases in women has decreased in the United States and Europe since the 1960s, the number of breast cancer cases in men have not decreased, but remained stable or slightly increased.

The rate of increase in cases begins and steadily rises at age 50 for men. However, the average age for male breast cancer is between 60 and 70 years old, with a median age of 67 years. Men often are diagnosed at a later stage than women.

Causes and symptoms

Scientists do not know what causes most cases of male breast cancer. However, excellent progress is being made in genetic research and in understanding how genes instruct cells to grow, divide, and die. For example, researchers have now mapped all of the genes in the human body. Genes are part of the body’s DNA, which is the chemical that instructs the cells. When DNA or genes carry defects (mutations), they activate changes in the cells, such as rapid cell division, that lead to cancer. Some genes, called tumor suppression genes, cause cells to die. Scientists have identified some genetic mutations that are risk factors for breast cancer. In other cases, environmental, or outside, factors are thought to increase a man’s risk for breast cancer.

Mutations of at least two versions of a tumor suppressor gene (BRCA1 and BRCA2) have been identified as causes of breast cancer in women. In men, the BRCA2 mutation is considered responsible for about 15% of breast cancers. Men can inherit genes from either parent. Studies have shown that BRCA1 also may increase a man’s risk for breast cancer, but its role is less certain. These mutations have been shown to increase other cancers in men, including prostate cancer. Klinefelter’s syndrome is a rare genetic cause of breast cancer in men. It results from inheriting an additional X chromosome.

Several other factors also may cause male breast cancer. Some conditions, such as the liver disease cirrhosis, can cause an imbalance in a man’s hormones, producing high levels of the female hormone estrogen, which can lead to breast cancer. Exposure to some substances such as high amounts of radiation may contribute to male breast cancer. A 2004 report studied why a cluster of breast cancer cases occurred among a small group of men who worked in the basement office of a multi-story office building. The study linked their breast cancer to exposure to high magnetic fields from a nearby electrical switchgear room in their work space.

Many men do not realize they can develop breast cancer; they ignore the symptoms. The most common symptom is a mass, or lump in the chest area, particularly around the nipple. The lump will be firm, not tender or painful. Other signs that may warn of male breast cancer include:

• Skin dimpling or puckering
• Changes in the nipple, such as drawing inward (retraction)
• Nipple discharge of any kind
• Redness or scaling of the nipple or breast skin
• Abnormal swelling (or lump) of the breast, nipple, or chest muscle
• Prolonged rash or irritation of the nipple, which may indicate Paget’s disease

Diagnosis

Physicians follow the same steps for diagnosing breast cancer in men as in women, except that routine screening of breast cancer is not done in men. Once symptoms are noticed, however, physicians will proceed in the same way. The physician will conduct a thorough medical history and examination, including questions that may identify risk factors for breast cancer, such as male or female relatives with the disease. The medical history also helps gather details on possible symptoms for breast cancer.

The physician also performs a clinical breast examination. This helps locate and study a lump or suspicious area. The physician will feel (palpate) a mass to get an idea of its size, texture, likely location and relation to surrounding skin, muscles and tissues. At this point, the physician already will begin to look for signs that the cancer may have spread to other organs and to the lymph nodes. The physician will palpate lymph nodes and the liver, for instance, to see if they are enlarged.

The next step in diagnosis usually is a diagnostic mammogram. Mammography is an x ray of the breast. Mammograms are performed by radiologic technologists who take special training in the procedure. Mammograms are evaluated by radiologists, physicians who receive medical training specifically in interpreting x rays. If the initial mammogram shows suspicious findings, the radiologist may order magnification views to more closely look at the suspicious area. Mammograms can accurately show the tissue in the breast, even more so in men than women, because men do not have dense breasts or benign cysts in their breasts that interfere with the diagnosis.

The radiologist also might recommend an ultrasound to follow up on suspicious findings. Ultrasound often is used to image the breasts. Also known as sonography, the technique uses high-frequency sound waves to take pictures of organs and functions in the body. Sound wave echoes can be converted by computer to an image and displayed on a computer screen. Ultrasound does not use radiation. A technologist will perform the ultrasound; it will be evaluated by the radiologist.

Biopsies, which involve removing a sample of tissue, are the only definite way to tell if a mass is cancerous. At one time, surgical biopsies were the only option, requiring removal of all or a large portion of the lump in a more complicated procedure. Today, fine-needle aspiration biopsy and core biopsies can be performed. In fine-needle aspiration biopsy, a thin needle is inserted to withdraw fluid from the mass. The physician may use ultrasound or other imaging guidance to locate the mass if necessary. The fluid is tested in a laboratory under a special microscope to determine if it is cancerous.

A core biopsy is similar, but involves removing a small cylinder of tissue from the mass through a slightly larger needle. Core biopsy may require local anesthesia. These biopsy techniques usually can be performed in a physician office or outpatient facility. The cells in biopsy samples help physicians determine if the lump is cancerous and the type of breast cancer. A tissue sample also may be used for assigning a grade to the cancer and to test for certain proteins and receptors that aid in treatment and prognosis decisions.

If there is discharge from the nipple, the fluid also may be collected and analyzed in a laboratory to see if cancer cells are present in the fluid.

Diagnosis of breast cancer spread may require additional tests. For example, a computed tomography (CT) scan may be ordered to check organs such as the liver or kidney for possible metastasized cancer. A chest x ray can initially check for cancer spread to the lungs. Bone scans are nuclear medicine procedures that look for areas of diseased bone. Magnetic resonance imaging (MRI) has been increasingly used in recent years as a follow-up study to mammograms when findings are not clear. However, for metastatic breast cancer, they are more likely to be ordered to check for cancer in the brain and spinal cord. Positron emission tomography (PET) scans also have become more common in recent years.

Treatment team

The treatment team for male breast cancer normally consists of a primary care physician, a medical oncologist (cancer specialist) and if radiation therapy is used, a radiation oncologist. Many other staff also are involved. For instance, special oncology nurses help guide patients through their care and recovery. Radiation therapists are specially trained technologists who deliver the radiation therapy treatments prescribed by the radiation oncologist.

Clinical staging, treatments, and prognosis

A technique called sentinel lymph node biopsy may be the first step in staging. The sentinel node is the first one the cancer cells are likely to reach, so it is the first one checked for cancerous cells. Using a radioactive substance and blue dye injected into the area around the tumor, physicians can track the path of the cells and stage the cancer. The technique has been used for many years on women with breast cancer; research in 2004 showed it worked well for predicting lymph node status in men as well.

Staging

Cancer staging systems help physicians compare treatments and research and identify patients for clinical trials. Most of all, they help physicians determine treatment and prognosis for individual patients by describing how severe a patient’s cancer is in relation to the primary tumor. The most common system used for cancer is the American Join Committee on Cancer (AJCC) TNM system, which bases staging largely on the spread of the cancer. T stands for tumor and describes the tumor’s size and spread locally, or within the breast and to nearby organs. The letter N stands for lymph nodes and describes the cancer’s possible spread to and within the lymph node system. In some descriptions below, the cancer may have been found by sentinel node biopsy as microscopic disease in nodes that are in the breasts (rather than the armpits). For simplification, these findings have been grouped with the axillary lymph nodes. M stands for metastasis to note if the cancer has spread to distant organs. Further letters and numbers may follow these three letters to describe number of lymph nodes involved, approximate tumor sizes, or other information. The following is a summary of breast cancer stages:

Stage 0: Tis, N0, M0: Ductal carcinoma in situ (DCIS). This is the earliest and least invasive form of breast cancer; the cancer cells are located within a duct and have not invaded surrounding fatty tissue.

Stage I: T1, N0, M0: The tumor is less than 1 in. in diameter (2 cm or less) and has not spread to lymph nodes or distant organs.

Stage IIA: T0, N1, M0/T2, NO, MO: No tumor is found or the tumor is smaller than 2 cm and cancer is found in one to three axillary lymph nodes (even if no tumor is found), or the tumor is between 2 and 5 cm in diameter but has not spread to the axillary lymph nodes. The cancer has not spread to distant organs.

Stage IIIB: T2, N1, M0/T3, NO, MO: The tumor is between 2 and 5 cm in diameter and has spread to one to three axillary lymph nodes or the tumor is larger than 5 cm, has not grown into the chest wall or spread to the lymph nodes or distant organs.

Stage IIIA: T0-2, N2, M0/T3, N1, MO: The tumor is smaller than 5 cm in diameter and has spread to four to nine axillary lymph nodes or the tumor is larger than 5 cm and has spread to one to nine axillary lymph nodes. The cancer has not spread to distant organs.

Stage IIIB: T4, N0-2, M0: The tumor has grown into the chest wall or the skin and may have spread to no lymph nodes or as many as nine lymph nodes. Cancer has not spread to distant sites.

Stage IIIC: T0-4, N3, MO: The tumor is any size, has spread to 10 or more axillary lymph nodes or to one or more lymph nodes under or above the collarbone (clavicle) on the same side as the breast tumor. The cancer has not spread to distant organs.

Inflammatory breast cancer: Classified as stage III, unless it has spread to distant organs or lymph nodes not near the breast (which would classify it as Stage IV).

Stage IV: T0-4, N0-3, M1: Regardless of the tumor’s size, the cancer has spread to distant organs, such as the liver, bones, or lung, or to lymph nodes far from the breast.

Treatment

If the axillary lymph nodes were identified as containing cancer at the time of the sentinel lymph node biopsy, they will be removed in an axillary dissection. Sometimes, this is done at the time of the biopsy.

For Stage I, surgery often is the only treatment needed for men. Women often have lumpectomies, which remove as little surrounding breast tissue as possible, to preserve some of their breast shape. For men, this is less of a concern, and mastectomy, or surgical removal of the breast, is performed in 80% of all male breast cancers. Men with Stage I tumors larger than 1 cm may receive additional (adjuvant) chemotherapy.

Men with Stage II breast cancer also usually receive a mastectomy. If they have cancer in the lymph nodes, they probably will receive adjuvant therapy. Those with estrogen receptor-positive tumors may receive hormone therapy with tamoxifen. The treatment team may recommend adjuvant radiation therapy if the cancer has spread to nearby lymph nodes and/or to the skin.

Stage III breast cancer requires mastectomy followed by adjuvant therapy with tamoxifen when hormones are involved. Most patients with Stage III disease also will require chemotherapy and radiation therapy to the chest wall.

Men with Stage IV breast cancer will require systemic therapy, or chemotherapy and perhaps hormonal therapy that works throughout the body to fight the cancer in the breast, as well as the cancer cells that have spread. Patients also may receive immunotherapy to help patients fight infection following chemotherapy. Radiation and surgery also may be used to relieve symptoms of the primary cancer and areas where the cancer may have spread. The treatment team also may have to diagnose specific treatments for the metastatic cancers, depending on their sites.

If male breast cancer recurs in the breast or chest wall, it can be treated with surgical removal and followed by radiation therapy. An exception is recurrence in the same area, where additional radiation therapy can damage normal tissue. Recurrence of the cancer in distant sites is treated the same as metasteses found at the time of diagnosis.

Prognosis

Prognosis for male breast cancer varies, depending on stage. Generally, prognosis is poorer for men than for women, because men tend to show up for diagnosis when their breast cancer has reached a later stage. The average five-year survival rate for Stage I cancers is 96%. For Stage II, it is 84%. Stage III cancers carry an average five-year survival rate of 52%, and by Stage IV, the rate drops to 24%.

Alternative and complementary therapies

Many alternative and complementary therapies can help cancer patients relax and deal with pain, though none to date have been shown to treat or prevent male breast cancer. For example, traditional Chinese medicine offers therapies that stress the importance of balancing energy forces. Many studies also show that guided imagery, prayer, meditation, laughter, and a positive approach to cancer can help promote healing. Early studies have shown that soy and flaxseed may have some preventive properties for breast cancer. However, these trials have been conducted in women. When looking for these therapies, cancer support groups suggest asking for credible referrals and working with the medical treatment team to coordinate alternative and complementary care.

Coping with cancer treatment

It is difficult for some men to accept and cope with a breast cancer diagnosis, since it is a relatively rare and unexpected disease among men. It is important that men work closely with their treatment team to talk about the their concerns and to carefully follow all instructions for care. Support groups and family support are critical in coping with a breast cancer diagnosis.

Eating a nutritious diet, stopping use of tobacco, and limiting use of alcohol, can help in recovery from breast cancer. Beginning a regular exercise program when the treatment team recommends also helps.

Clinical trials

Research currently is underway to test various chemotherapy combinations for male breast cancer at different stages. A clinical trial also is underway to investigate a vaccine for treating patients with metastatic breast cancer. The National Institutes of Health list clinical trials by disease type, including those for which they are recruiting patients. Choosing to participate in a clinical trial is a decision that involves the patient, family, and treatment team.

Prevention

Some forms of male breast cancer cannot be prevented. But detecting the cancer at an early stage can prevent serious complications, such as spread to distant organs. Men who have a history of breast cancer in their family should pay particular attention to the symptoms of breast cancer and seek immediate medical evaluation. Physicians may be able to test the blood of men with family history for presence of the BRCA2 gene so they may more carefully watch for early signs of breast cancer. Avoiding exposure to radiation also may help present some male breast cancers.

Special concerns

Men should remember that there are important difference between male and female breast cancers. Some experts say that specific guidelines and instructions for men with breast cancer are noticeably lacking, so men should not be afraid to ask questions or to push a physician for more information when he suspects he might have a suspicious lump or finding in his breast.