Breast Cancer, Cancer, Health,

The Structure Of Breast

For a better understanding of all aspects of breast care, women should know the basics of breast anatomy and function.

Throughout the ages, the female breast has been linked with sensuality and sexual attractiveness. In almost all cultures, men are sexually attracted by the female breast. From puberty onward, women are deeply concerned about their breasts; their size and shape are often equated with femininity and physical attractiveness.

While the breast is not vital to reproduction, and breast size is unrelated to sexual responsiveness, myths regarding both persist. It is little wonder that women fear breast cancer and mastectomy more than other forms of the disease. For example, lung cancer, which now kills more women each year than breast cancer does, is not regarded with the same sense of dread.

The healthy breast of a mature woman is composed mostly of fat and glandular tissue. Its primary function is to produce milk to feed a newborn infant. To envision the internal milk-producing apparatus of a breast, think of a bunch of grapes. The grapes represent the clusters of milk-secreting glands (lobules), while the stems represent the hollow ducts that carry the milk from the glands to the nipple. These lobules and ducts are immersed in fatty tissue, which gives the breast its contour and softness. The breast itself has no muscles, but lies on top of the pectoralis major, a large muscle which stretches from the breastbone and collarbone to an attachment point on the shoulder. The breast is held together by fibrous tissue called Cooper’s ligaments.

A network of blood vessels brings nutrients and hormones to the breast tissue. Increased blood flow during the menstrual cycle, pregnancy, and sexual stimulation causes the blood vessels to become engorged. Overall variation in breast size depends on the amount of fat surrounding and protecting the internal structures of the breasts.

The majority of breast cancers are initially detected by the women themselves who discover the presence of a suspicious lump. Although discovering a lump can be alarming so much so that many women delay seeing a doctor, fearing they will only have their worst suspicions confirmed—the fact is that about four out of five turn out to be benign cysts or other harmless conditions. Each month the breast goes through cyclical changes as it responds to fluctuating hormone levels. Stimulated by estrogen and then progesterone, the breasts become somewhat engorged with extra blood and fluid; the ducts swell and proliferate. These changes take place in anticipation of pregnancy and subsequent milk production. If conception does not take place, the swelling and other changes subside with the onset of menstruation.

After a few years of these cyclical changes, the breasts may develop varying degrees of lumpiness. These lumps are made up of fibrous tissue and tiny cysts and are referred to as fibrocystic changes. The lumps are most prominent in the premenstrual period, and they may produce considerable breast tenderness. Fibrocystic change usually subsides after menopause, but may persist in women who take estrogen replacement or who continue to have relatively high levels of sex hormones produced by the adrenal glands. Usually these benign lumps can be distinguished from cancer; they tend to come and go according to the menstrual cycle and they have a somewhat different feel from a true tumor or a cancer. Mammography and aspiration may be helpful in distinguishing fibrocystic change from cancer. But there are instances in which it is impossible to tell whether the lump is benign or malignant except by a surgical biopsy.

Most breast cancer, as well as benign fibrocystic conditions, begins in the lining of the milk ducts, or sometimes in the lobules themselves. When it is confined to the inside of a duct or lobule, it is referred to as carcinoma in situ a noninvasive stage that may remain dormant for years before spreading. In this dormant stage, it is 100 percent curable by surgical removal. Also, a certain percentage of carcinoma in situ never develops into invasive cancer.

Small vessels called lymphatics drain fluids and impurities from the breasts in two ways: lymph ducts between the shoulder and the nipple lead to lymph nodes in the armpits; lymph ducts between the nipples lead to nodes by the breastbone, under the ribs.

The lymphatic system is a key component of the body’s immune system. The lymphatic fluid contains white blood cells lymphocytes which are instrumental in the production of antibodies. All body cells are bathed by lymph fluid, which is transported through the body by the lymphatic vessels. The lymph nodes contain high concentrations of white blood cells, and these nodes function as filters for foreign substances bacteria, viruses, tumor cells and so forth. This is why the lymph ducts and nodes are a common route for the spread of breast cancer. The cancer also may spread to other parts of the body via the bloodstream.

Breast development is one of the physical changes that signal the onset of puberty. Growth of the breasts and other aspects of sexual maturity are controlled by the hormonal changes that occur during puberty. Development begins with enlargement and darkening of the areola—the tissue surrounding the nipple followed by enlargement of die breast. Frequently one breast will begin developing before the other, or the size will be uneven. Although this often is a concern to both the girl and her parents, uneven breast development is very common, and unless a breast fails to develop completely it is seldom cause for worry.

Breast appearance varies greatly from woman to woman. Size, shape, and prominence of nipples, areola, and Montgomery glands (the sebaceous glands in the areola that sometimes look like small pimples) all are highly individualistic. Breast appearance changes at different stages of a woman’s life. During pregnancy, for example, the areola darkens, the nipples may become more prominent, and the breast enlarges. In the premenstrual phase of the monthly cycle, many women experience an increase in breast “lumpiness” and size; the breasts also may be tender or even painful. During sexual arousal or exposure to cold the nipples may become erect. Nipple size and appearance also vary; in some women the nipples may be flat or even inverted; in others they may be very prominent or have a mulberry shape. All these variations are normal; each woman should become familiar with her own breasts and know how they change at different times in her monthly cycle.

Breasts also change with age. After menopause, breast tissue becomes less dense as the milk glands and ducts shrink, with a resulting reduction in size. Some sagging also may occur. Weight gain or loss can alter breast size, although many thin women are large-breasted and, conversely, there are many obese women with small breasts. Contrary to popular belief, exercise and body-building routines do not increase breast size, primarily because the breasts do not contain muscles.