Last reviewed and revised by Faculty of Harvard Medical School on January 24, 2013
By Harvey B. Simon, M.D.
Harvard Medical School
Health problems are intensely private affairs, but men like Senator John Kerry and General Colin Powell are increasingly forthright about prostate cancer.
Still, most guys are reluctant to own up to "women's problems" like breast disease. But men have breasts, too.
The male breast is much smaller than its female counterpart. It also has a simpler structure as it can't produce milk. This makes breast disease much less common in men than women. But men can develop benign and malignant breast problems. Early detection is the key to preventing more serious illness or death, so every man should understand the basic elements of male breast disease.
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Hormones and the Male Breast
Men and women make both male and female hormones. In men, the male hormone testosterone and other androgens are dominant; they keep the breast tissue small. In women, the hormone estradiol and other estrogens have the upper hand. Men also have small amounts of estradiol, which is a byproduct of testosterone metabolism.
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Benign Breast Enlargement
Enlargement of the male breast, called gynecomastia, is usually benign harmless and is often reversible.
Some men have prominent breasts because they are overweight. But true gynecomastia is caused by an enlargement of the breast's glandular tissues, not by excess fat. The glandular tissue is concentrated under the nipple, but fat is spread around the whole breast.
Gynecomastia is very common during adolescence. Up to 70% of boys experience it at puberty. It is usually mild and short-lived. It is much less common in adulthood, occurring in fewer than 1% of men. Two-thirds of the men who have gynecomastia have it in both breasts. The breast enlargement is usually mild and painless, but about a third of men complain of tenderness.
The most common causes of gynecomastia are liver disease and certain medications. Each accounts for about 25% of cases.
- Liver disease - One of the liver's many purposes is to break down estrogens. Liver disease, especially alcoholic cirrhosis, weakens that ability. Estrogen levels may rise, which enlarges the breasts. If liver function improves, which rarely happens in cirrhosis, the breasts can return to their usual size.
- Medications - Certain drugs may cause gynecomastia.
- Digoxin (Lanoxin), used for heart disease
- Spironolactone (Aldactone), a diuretic
- Cimetidine (Tagamet), used for gastritis, ulcers and heartburn
- Ketoconazole (Nizoral), used for fungal infections
- Finasteride (Proscar) and dutasteride (Avodart), used for benign prostatic hyperplasia (BPH)
Herbal remedies that contain phytoestrogens are also responsible for breast enlargement. Street drugs like marijuana, amphetamines and heroin can all cause gynecomastia along with much more serious problems. The breasts will return to their normal size once a person stops taking the offending drug or medication.
- Treatment of prostate cancer - Because prostate cells are stimulated by androgens, a major goal of treatment of advanced prostate cancer is to reduce androgen levels. One way to do this is by surgically removing the testicles. The other way is with drug therapy. Some medications can reduce the amount of testosterone and other androgens the body makes that stimulate the cancer to grow. Others, called anti-androgens, can block the effects of testosterone and other androgens. Another option is to give estrogen, which can also prevent the testicles from making testosterone.
All of these treatments, while helpful, can cause gynecomastia. Anti-androgens and estrogens pose the highest risk. More than half the men who receive androgen deprivation therapy the general term for drug therapy that blocks the production or action of testosterone develop gynecomastia. Fortunately, it is usually mild and can be controlled by radiation or surgery if it's troublesome. And new research shows that tamoxifen, an anti-estrogen medication used for breast cancer in men and women, is very effective for benign breast enlargement triggered by prostate cancer treatment and other causes.
Less common causes of gynecomastia include:
- Testicular cancer It's uncommon, but every man with breast enlargement should have his testicles checked.
- Recovery from malnutrition or from a serious chronic illness
- An overactive thyroid gland
- Declining testosterone levels with age
- Klinefelter's syndrome About 1 in 2,000 boys are born with an extra X (female sex) chromosome.
- Testicular failure
- Various estrogen-producing tumors
These diverse disorders have two things in common: low androgen levels and high estrogen levels. But competitive athletes and men who take "Andro" (androstenedione supplements) or abuse male steroid hormones can also develop gynecomastia. That's because part of everyone's androgens are converted to estrogens; men who boost their androgens to artificially high levels get abnormally high estrogen levels in the bargain.
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Male Breast Cancer
About 2,000 American men will develop breast cancer each year. This is quite a small number compared with the over 200,000 American women who will be diagnosed with the disease. Still, the incidence of male breast cancer has risen 25% in the past 25 years, and about 400 men will die from the disease this year. While it's a far cry from the 40,000 breast cancer deaths in women, it's a reminder that the early diagnosis and treatment of breast cancer can save men's lives, too.
Most men with breast cancer notice the problem themselves. A firm, painless lump appears, usually under the nipple. The nipple itself is often ulcerated, but bleeding or discharge is rare.
The lump that signals breast cancer is much firmer than the tissue of benign breast enlargement. In fact, gynecomastia does not increase a man's risk of developing breast cancer.
The average man with breast cancer is 60 - 70 years old. Although the causes of male breast cancer are not known, there are known risk factors:
Breast cancer is rare in men. Nevertheless, pay attention to changes. If you notice an abnormal thickening or lump near one of your nipples, ask your doctor to check it. He may order a mammogram or ultrasound. Based on the results, the next step may be a surgical biopsy or a fine needle aspiration. (The doctor sucks cells from the mass into a syringe, and then examines them in the laboratory.)
Surgery (modified radical mastectomy) is the standard treatment for male breast cancer. Because most of these tumors have estrogen receptors, anti-estrogen therapy with the drug tamoxifen is often helpful. Radiation and chemotherapy also help, just as they do for female breast cancer.
Male breast cancer responds quite well to treatment. The overall 5-year survival rate is about 60%. Early diagnosis can raise that to 90%.
When men think about breasts, it's usually not their own that come to mind. Indeed, breast disease is not a "guy" thing. But men should listen to their bodies, which means noting any changes in their breasts. Bleeding, milky discharge from the nipple or uneven breast enlargement require immediate attention. Fortunately, when breast enlargement occurs, it is usually more worrisome than serious. Still, a medical examination can reassure many and provide lifesaving treatment to some.