Breast cancer is the most common malignancy in women and the second leading cause of cancer death, exceeded only by lung cancer in 1985. One woman in eight who lives to age 85 will develop breast cancer at some time during her life.
At present there are over 2 million women living in the United States who have been treated for breast cancer. About 41,000 women will die from the disease. The chance of dying from breast cancer is about 1 in 33. However, the rate of death from breast cancer is going down. This decline is probably the result of early detection and improved treatment.
Breast cancer is not just a woman’s disease. The American Cancer Society estimates that 1600 men develop the disease yearly and about 400 may die from the disease.
Breast cancer risk is higher among those who have a mother, aunt, sister, or grandmother who had breast cancer before age 50. If only a mother or sister had breast cancer, your risk doubles. Having two first-degree relatives who were diagnosed increases your risk up to five times the average.
Although it is not known exactly what causes breast cancer; sometimes the culprit is a hereditary mutation in one of two genes, called BRCA1 and BRCA2. These genes normally protect against the disease by producing proteins that guard against abnormal cell growth, but for women with the mutation, the lifetime risk of developing breast cancer can increase up to 80 percent, compared with 13 percent among the general population. In effect, more than 25 percent of women with breast cancer have a family history of the disease.
For women without a family history of breast cancer, the risks are harder to identify. It is known that the hormone estrogen feeds many breast cancers, and several factors – diet, excess weight, and alcohol consumption – can raise the body’s estrogen levels.
Early signs of breast cancer include the following:
- A lump which is usually single, firm and most often painless is detected.
- An area of the skin on the breast or underarm is swollen and has an unusual appearance.
- Veins on the skin surface become more prominent on one breast.
- The affected breast nipple becomes inverted, develops a rash, changes in skin texture, or has a discharge other than breast milk.
- A depression is found in an area of the breast surface.
Types and Stages of Breast Cancer
There are many different varieties of breast cancer. Some are fast-growing and unpredictable, while others develop more slowly and steady. Some are stimulated by estrogen levels in the body; some result from mutation in one of the two previously mentioned genes – BRCA1 and BRCA2.
Ductal Carcinoma In-Situ (DCIS): Generally divided into comedo (blackhead), in which the cut surface of the tumor shows extrusion of dead and necrotic tumor cells similar to a blackhead, and non-comedo types. DCIS is early breast cancer that is confined to the inside of the ductal system. The distinction between comedo and non-comedo types is important, as comedocarcinoma in-situ generally behaves more aggressively and may show areas of micro-invasion through the ductal wall into surrounding tissue.
Infiltrating Ductal: This is the most common type of breast cancer, representing 78 percent of all malignancies. On mammography, these lesions can appear in two different shapes — stellate (star- like) or well circumscribed (rounded). The stellate lesions generally have a poorer prognosis.
Medullary Carcinoma: This malignancy comprises 15 percent of breast cancers. These lesions are generally well circumscribed and may be difficult to distinguish from fibroadenoma by mammography or sonography. With this type of breast cancer, prognostic indicators estrogen and progesterone receptor are negative 90 percent of the time. Medullary carcinoma usually has a better prognosis than other types of breast cancer.
Infiltrating Lobular: Representing 15 percent of breast cancers, these lesions generally appear in the upper outer quadrant of the breast as a subtle thickening and are difficult to diagnose by mammography. Infiltrating lobular can involve both breasts (bilateral). Microscopically, these tumors exhibit a linear array of cells and grow around the ducts and lobules.
Tubular Carcinoma: This is described as orderly or well-differentiated carcinoma of the breast. These lesions make up about 2 percent of breast cancers. They have a favorable prognosis with nearly a 95 percent 10-year survival rate.
Mucinous Carcinoma: Represents 1-2 percent of carcinoma of the breast and has a favorable prognosis. These lesions are usually well circumscribed (rounded).
Inflammatory Breast Cancer: This is a particularly aggressive type of breast cancer that is usually evidenced by changes in the skin of the breast including redness (erythema), thickening of the skin and prominence of the hair follicles resembling an orange peel. The diagnosis is made by a skin biopsy, which reveals tumors in the lymphatic and vascular channels about 50 percent of the time.
Stages of Breast Cancer
The most common type of breast cancer is ductal carcinoma. It begins in the lining of the ducts. Another type, called lobular carcinoma, arises in the lobules. When cancer is found, the pathologist can tell what kind of cancer it is – whether it began in a duct (ductal) or a lobule (lobular) and whether it has invaded nearby tissues in the breast (invasive).
When cancer is found, special lab tests of the tissue are usually done to learn more about the cancer. For example, hormone (estrogen and progesterone) receptor tests can help determine whether hormones help the cancer to grow. If test results show that hormones do affect the growth of the cancer (a positive test result), the cancer is likely to respond to hormonal therapy. This therapy deprives the cancer cells of estrogen.
Other tests are sometimes done to help predict whether the cancer is likely to progress. For example, x-rays and other lab tests are done. Sometimes a sample of breast tissue is checked for a gene, known as the human epidermal growth factor receptor-2 (HER-2 gene) that is associated with a higher risk that the breast cancer will recur. Special exams of the bones, liver, or lungs are done because breast cancer may spread to these areas.
A woman’s treatment options depend on a number of factors. These factors include her age and menopausal status; her general health; the size and location of the tumor and the stage of the cancer; the results of lab tests; and the size of her breast. Certain features of the tumor cells, such as whether they depend on hormones to grow are also considered.