Breasts are a pair of glandular organs of the human female that secrete milk for nourishing a newborn infant. The breast consists of 15 to 25 irregularly shaped lobes. Between the lobes are connective tissue and large amounts of adipose (fat) tissue. Leading from each lobe is a duct, the lactiferous duct, which opens to the outside at the nipple. Surrounding the nipple is a pig-mented circular area called the areola. Before pregnancy the areola is pink, but it turns brown during pregnancy and remains dark throughout life.
Development and Milk Production
The growth of the breasts is controlled by two female sex hormones: estradiol (an estrogen hormone) and progesterone, which are first produced in large quantities at puberty. During pregnancy, the increased production of these hormones stimulates the breasts to enlarge greatly. Milk secretion is controlled by a third hormone, prolactin, secreted by the pituitary gland during the later stages of pregnancy. Stimulated by prolactin, the cells of the lobules begin secreting milk.
Although milk is secreted continuously, it does not flow easily into the lactiferous ducts and must be forced into them. This process, called milk ejection or milk letdown, is stimulated by the infant suckling at the breast. As he suckles, nerve impulses from the nipple travel through the spinal cord to the hypothalamus of the brain. The hypothalamus then secretes a hormone, called oxytocin, which causes the cells surrounding the lobules to contract, forcing the milk inside the lobules into the ducts. Although this process involves several steps, it takes only about 30 seconds.
Examination for Breast Cancer
The importance of frequent, regular examinations for lumps in the breast tissue can hardly be overstated. When breast cancer is detected and treated very early, the patient has about a 90% chance of surviving five years. The survival rate for patients treated after the cancer has become extensive drops to about 50%.
To detect cancer at an early stage, every woman should examine her breasts at weekly intervals. A more extensive examination should be made at least twice a year by a gynecologist or surgeon, especially if two or more of the patient's blood relatives have had any type of cancer. Unfortunately "young" cancers of the breast seldom cause pain. If they did, far more women would consult their physicians at an early stage when treatment is most effective.
When a woman feels any lump - regardless of size - in a breast, she should immediately consult a gynecologist or surgeon. If the nature of the lump is in doubt, the lump should be removed for a tissue examination, or biopsy. Before surgery the patient's permission is usually obtained for a further operation, so that if the biopsy proves the presence of cancer, more extensive surgery can be performed without delay.
In recent years the diagnosis of breast cancer has been helped considerably by the use of three new types of tests- mammography, xerography, and thermography. Mammography detects tumors by means of X rays. Xeroradiography is an X-ray technique in which the image is formed by a Xerographic process, with increased sensitivity of tumor detection. Thermography, which is sensitive to small temperature differences, can detect "hot" spots created by tumors. When combined, these tests are about 85%-90% accurate.
The proper surgical treatment for cancer of the breast has been the subject of considerable controversy. The operations vary from lumpectomy, which removes only the cancerous lump; through simple mastectomy, in which the breast and associated lymph nodes are removed; to radical mastectomy, in which the underlying pectoral muscles as well as the breast and lymph nodes are removed. Lumpectomy is often recommended for very old women, past 75 or 80 years of age, because only one out of four women in this age group has a recurrence of cancer within five years following the operation. A point in favor of removing the entire breast, by either simple or radical mastectomy, is that in one case out of eight cancer is found in areas of the breast other than the ones detected before operation.
Most physicians in the United States prefer the usual radical mastectomy, insisting that this operation gives by far the best five- and ten-year survival rates. However, in the early 1970's many surgeons who previously performed radical operations began performing simple mastectomies, relying on evidence that the success rate is about the same for both types of operations.
A Scientific Look At Breasts
Following breast surgery for cancer, postoperative X-ray or cobalt radiation treatment - and in some cases chemotherapy - may be carried out. The type of treatment depends on the findings of the pathologist.
If the lymph nodes do not show any evidence of cancer, treatment by either X-ray or cobalt radiation is not necessary. Chemotherapy usually is not part of the routine treatment following mastectomy. It is reserved instead for patients who have recurrences of cancer.