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Archive for June 5th, 2010

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A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung, mouth, larynx (voice box), bladder, kidney, and several other organs.

But risk factors don’t tell us everything. Having a risk factor, or even several, does not mean that you will get the disease. Some men with one or more breast cancer risk factors never develop the disease, while most men with breast cancer have no apparent risk factors. Even when someone has a risk factor, there is no way to prove that it actually caused the cancer.

We don’t yet completely understand the causes of breast cancer in men, but researchers have found several factors that may increase the risk of getting it. As with female breast cancer, many of these factors are related to sex hormone levels in the body.

Aging

Aging is an important risk factor for the development of breast cancer in men. Men with breast cancer are on average about 67 years old when they are diagnosed.

Family history of breast cancer

Breast cancer risk is increased if other members of the family (“blood relatives”) have had breast cancer. About 1 out of 5 men with breast cancer have close male or female relatives with the disease.

Inherited gene mutations

A mutation (change) in the BRCA2 gene, which is responsible for some breast cancers in women, probably accounts for about 1 in 10 breast cancers in men. BRCA1 mutations can also cause breast cancer in men, but they seem to be responsible for fewer cases than mutations in the BRCA2 gene. People with these mutations typically have a strong family history of breast cancer, when they are younger age (under 60).

Other mutations that may be responsible for some breast cancers in men include those in genes called CHEK2 and PTEN.

Klinefelter syndrome

This is a congenital condition (present at birth) that affects about 1 in 1,000 men. Normally the cells in men’s bodies have a single X chromosome along with a Y chromosome, while women’s cells have 2 X chromosomes. Men with this condition have cells with more than 1 X chromosome (sometimes as many as 4). This causes their testicles to be smaller than usual and they may not produce functioning sperm cells, making them infertile. Compared with other men, they have lower levels of androgens (male hormones) and more estrogens (female hormones). For this reason, they often develop gynecomastia (benign male breast growth).
Some studies have found that men with Klinefelter syndrome are more likely to get breast cancer than other men. One study of men with this syndrome found that the risk of getting breast cancer was about 1%. But this is a hard area to study because these are both uncommon problems, and it is hard to collect enough cases to be sure. The risk seems to be increased, but overall it is still low because this is such an uncommon cancer, even for men with Klinefelter syndrome.

Radiation exposure

A man whose chest area has been treated with radiation (usually for treatment of a cancer inside the chest, such as lymphoma) has an increased risk of developing breast cancer.

Alcohol

Heavy drinking (of alcoholic beverages) increases the risk of breast cancer in men. This may be because of its effects on the liver .

Liver disease

The liver plays an important role in sex hormone metabolism by making binding proteins that carry the hormones in the blood. These binding proteins affect the hormones’ activity. Men with severe liver disease such as cirrhosis have relatively low levels of androgens and higher estrogen levels. Therefore, they may have an increased risk of developing breast cancer.

Estrogen treatment

Estrogen-related drugs are sometimes used in hormonal therapy for men with prostate cancer. This treatment may slightly increase their breast cancer risk. However, this risk is small compared with the benefits of this treatment in slowing the growth of prostate cancer.

Men taking high doses of estrogens as part of a sex change procedure may also have a higher breast cancer risk.

Obesity

Recent studies have shown that women’s breast cancer risk is increased by obesity (being extremely overweight) during her adult life. Obesity is probably a risk factor for male breast cancer as well. The reason is that fat cells in the body convert male hormones (androgens) into female hormones (estrogens). This means that obese men have higher levels of estrogens in their body. Some obese men may notice that they don’t have to shave as frequently as other men. They might also have trouble fathering children. Regular exercise and maintaining a healthy weight may help reduce the risk of breast cancer, as well as that of many other diseases and cancers.

Conditions affecting the testicles

Some studies have suggested that certain conditions that affect the testicles, such as having an undescended testicle, having mumps as an adult, or having one or both testicles surgically removed (orchiectomy) may increase breast cancer risk. More research is needed in this area.

Certain occupations

Some reports have suggested an increased risk in men who work in hot environments such as steel mills. This could be because long-term exposure to higher temperature can affect the testicles, which in turn would affect hormone levels. Men heavily exposed to gasoline fumes may also have a higher risk. Further research is needed to confirm these findings.

Last Medical Review: 01/14/2010
Last Revised: 01/14/2010

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Gynecomastia is the most common male breast disorder. It is not a tumor but rather an increase in the amount of a man’s breast tissue. Usually, men have too little breast tissue to be felt or noticed. A man with gynecomastia has a button-like or disk-like growth under his nipple and areola, which can be felt and sometimes seen. Although gynecomastia is much more common than breast cancer in men, both can be felt as a growth under the nipple, which is why it’s important to have any such lumps checked by your doctor.

Gynecomastia is common among teenage boys due to changes in the balance of hormones in the body during adolescence. It is also common in older men due to changes in their hormone balance.

In rare cases, gynecomastia occurs because tumors or diseases of certain endocrine (hormone-producing) glands cause a man’s body to make more estrogen (the main female hormone). Men’s glands normally make some estrogen, but it is not enough to cause breast growth. Diseases of the liver, which is an important organ in male and female hormone metabolism, can change a man’s hormone balance and lead to gynecomastia. Obesity (being extremely overweight) can also cause higher levels of estrogens in men.

Some medicines can cause gynecomastia. These include some drugs used to treat ulcers and heartburn, high blood pressure, and heart failure. Men with gynecomastia should ask their doctors if any medicines they are taking might be causing this condition.

Klinefelter syndrome, a rare genetic condition, can lead to gynecomastia as well as increase a man’s risk of developing breast cancer.

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It may help to understand some of the key words used to describe breast cancer.

Carcinoma:

This is a term used to describe a cancer that begins in the lining layer (epithelial cells) of organs such as the breast. Nearly all breast cancers are carcinomas (either ductal carcinomas or lobular carcinomas).

Adenocarcinoma:

An adenocarcinoma is a type of carcinoma that starts in glandular tissue (tissue that makes and secretes a substance). The ducts and lobules of the breast are glandular tissue (they make breast milk in women), so cancers starting in these areas are sometimes called adenocarcinomas.

Carcinoma in situ:

This term is used for the early stage of cancer, when it is confined to the layer of cells where it began. In breast cancer, in situ means that the abnormal cells remain confined to ducts (ductal carcinoma in situ, or DCIS) or lobules (lobular carcinoma in situ, or LCIS). They have not invaded into deeper tissues in the breast or spread to other organs in the body, and are sometimes referred to as non-invasive breast cancers.

Invasive (infiltrating) carcinoma:

An invasive cancer is one that has already grown beyond the layer of cells where it started (as opposed to carcinoma in situ). Most breast cancers are invasive carcinomas, either invasive ductal carcinoma or invasive lobular carcinoma.

Types of breast cancer in men

Ductal carcinoma in situ (DCIS)

In DCIS (also known as intraductal carcinoma), cancer cells form in the breast ducts but do not grow through the walls of the ducts into the fatty tissue of the breast or spread outside the breast. DCIS accounts for about 1 in 10 cases of breast cancer in men. It is almost always curable with surgery.

Infiltrating (or invasive) ductal carcinoma (IDC)

This type of breast cancer breaks through the wall of the duct and grows through the fatty tissue of the breast. At this point, it can spread (metastasize) to other parts of the body. At least 8 out of 10 male breast cancers are IDCs (alone or mixed with other types of invasive or in situ breast cancer). Because the male breast is much smaller than the female breast, all male breast cancers start relatively close to the nipple, so they are more likely to spread to the nipple. This is different from Paget disease as described below.

Infiltrating (or invasive) lobular carcinoma (ILC)

This type of breast cancer starts in the breast lobules (collections of cells that, in women, produce breast milk) and grows into the fatty tissue of the breast. ILC is very rare in men, accounting for only about 2% of male breast cancers. This is because men do not usually have much lobular tissue.

Lobular carcinoma in situ (LCIS)

In LCIS, abnormal cells form in the lobules, but they do not grow into the fatty tissue of the breast or spread outside the breast. Although LCIS is sometimes classified as a type of non-invasive breast cancer, most breast specialists think it is a risk factor for developing breast cancer rather than a true non-invasive cancer. As with invasive lobular carcinoma, LCIS is very rare in men.

Paget disease of the nipple

This type of breast cancer starts in the breast ducts and spreads to the nipple. It may also spread to the areola (the dark circle around the nipple). The skin of the nipple usually appears crusted, scaly, and red, with areas of itching, oozing, burning, or bleeding. The fingertips can be used to detect a possible lump within the breast.

Paget disease may be associated with DCIS or with infiltrating ductal carcinoma. It accounts for about 1% of female breast cancers and a higher percentage of male breast cancers.

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