Article updated and reviewed by Jennifer A. Ligibel, MD, Instructor in Medicine, Harvard Medical School, Dana-Farber Cancer Institute, Medical Oncology--Breast and Gynecologic Cancer on June 1, 2005.
Cancer is a disease characterized by the uncontrolled growth of abnormal cells. Breast cancer is any type of malignant (cancerous) growth in the breast tissue.
Breast cancer is the most common cancer in women and affects approximately one out of every eight women in the U.S.
There are several types of breast cancer, but the common types are ductal carcinoma (occurring in 85 - 90 percent of the cases) and lobular carcinoma (occurring in about eight percent of the cases).
Ductal carcinoma arises in the ducts (the passageway which carries milk from the milk-producing lobules to the nipple). Lobular carcinoma arises in the lobules (part of the lobe which ends in dozens of tiny bulbs that can produce milk).
No one knows exactly why a normal breast cell becomes a cancerous one, and there is probably no single cause. It is thought, however, that breast cancer results from a combination of risk factors. These risk factors can be grouped into several categories:
Hereditary risk: It has long been known that women whose mothers or sisters had breast cancer have a higher risk of developing the disease themselves. Recently, it has been discovered that breast cancer can develop when a woman inherits a breast cancer susceptibility gene from one of her parents. The most common of these genes are the BRCA1 and BRCA2 genes. These genes account for about 10 percent of all breast cancer cases and in families that have these genes, the risk of breast cancer can be very high. However, it is important to realize that 85 - 90 percent of breast cancers and NOT hereditary, and that all women need to be screened for breast cancer, even if no one in their families have ever had the disease.
Hormonal risk factors: The female hormones estrogen and progesterone are involved in breast cancer formation. For example, it is known that women who start to menstruate at an early age, or who have a late menopause have a higher risk of breast cancer than women who do not. It is also known that women who take hormone replacement therapy after menopause have an increased risk of breast cancer. Many studies have also been done looking at the risk of taking birth control pills. To date, these studies have not demonstrated an increased risk of breast cancer associated with use of these medications.
Age: Breast cancer becomes much more common as women grown older.
Gender: Most breast cancer occurs in women, although about 12,000 cases of breast cancer occur in men in the United States each year.
Diet and Exercise: Studies have shown that women who exercise are less likely to develop breast cancer than sedentary women. Studies have also shown that women who gain weight after menopause have an increased risk of breast cancer compared to women who do not. There are no clear links between diet and breast cancer risk, except for an increased risk of breast cancer in women who consume alcohol on a regular basis.
Early breast cancer usually does not cause pain. In fact, when it first develops, breast cancer may cause no symptoms at all. But as the cancer grows, it can cause these changes:
- a lump or thickening in the breast or armpit
- a change in the size or shape of the breast
- discharge from the nipple
- a change in the color or texture of the skin of the breast or areola (such as dimpling, puckering, or scaliness).
Note: any changes in the breast should be reported to a doctor without delay. Symptoms can be caused by cancer or by a number of less serious conditions. Early diagnosis is especially important for breast cancer because the disease responds best to treatment before it has spread. The earlier breast cancer is found and treated, the better a woman's chance for complete recovery.
- The doctor will examine the breasts using visual inspection and palpation. Visual inspection looks for changes in breast contour, new dimpling, nipple inversion, discharge, moles, puckering or persistent sores. Palpation is using the pads of the fingers to press down and feel the tissue around the breasts for any unusual lumps. Benign (non-cancerous) lumps may feel different from cancerous ones, but most times it is very difficult to determine whether a lump is cancerous without further testing.
- Mammography is an x-ray of the breast that reveals suspicious areas that are denser than normal breast tissue or have abnormal deposits of calcium. Mammography is an important screening test which can show a breast cancer long before it is big enough to be felt in the breast. Women over age 40 should undergo a mammogram every year in order to detect breast cancers when they are small and can be treated easily. Since mammograms have been used routinely in the United States, the death rate from breast cancer has fallen dramatically as cancers are found earlier, when they are more likely to be curable.
- Ultrasonography uses high frequency sound waves that enter the breast and bounce back. The pattern of their echoes produce a picture called a sonogram that detects whether the breast lump is solid (possibly cancerous) or filled with fluid (non-cancerous). An ultrasound is usually recommended to evaluate a palpable breast lump or an abnormality seen on a mammogram.
- Many times when an abnormality is felt in the breast or seen on a mammogram, the doctor will recommend a biopsy. In a biopsy, tissue is removed from the breast and examined by a pathologist, who can tell if cancerous cells are present. There are three ways to do breast biopsies: fine needle aspiration, large core breast biopsy and surgical biopsy. Fine needle aspiration (FNA) uses a fine needle, inserted into the breast tissue, to withdraw cells from the suspicious area. Large core breast biopsy uses a large core needle in a spring-loaded device that removes "cores" or plugs of tissue from the suspicious area. Surgical biopsy is the surgical removal of part or all of the lump or suspicious area.
If breast cancer is diagnosed, the doctor will then determine the stage (phase or progression) of the cancer. The following staging system is used:
- Carcinoma in situ is very early breast cancer. Cancer has not invaded into the normal breast tissue and is contained in either the breast duct (ductal carcinoma in situ) or the breast lobule (lobular carcinoma in situ). By definition, this type of cancer is not invasive and is not able to travel to the lymph nodes or other parts of the body.
- Stage I means the tumor is no larger than two centimeters (cm) (about one inch) and has not spread outside the breast.
- Stage II means the tumor is from two to five cm (roughly two inches) and/or has spread to the lymph nodes under the arm.
- Stage III means the cancer is larger than five cm (about two inches) involves the underarm lymph nodes to a greater extent, and/or has spread to other lymph nodes or other tissues near the breast.
- Stage IV means the cancer has spread to other organs of the body (metastatic cancer), most often the lungs, bones, and/or liver.
There are two methods of treatment - local and systemic.
Local treatments are used to remove or destroy the cancer cells in a specific area. Surgery and Radiation therapy are examples of local treatments.
Systemic treatments are used to destroy or control cancer cells all over the body. Chemotherapy and hormonal therapy examples of systemic treatments.
The right treatment method, however, depends on the size and location of the breast tumor; the results of the pathologist’ s review of the tumor specimen, the woman's age, menopausal status, and general health; and the stage of the disease.
Surgery is the most common treatment for breast cancer. There are two types: breast-sparing surgery and mastectomy.
Breast-sparing surgery, also known as lumpectomy or partial mastectomy, removes the cancerous lump but not the entire breast. This is generally accompanied by a sampling of the under arm lymph nodes to see if the cancer has spread to this area. This sampling can either by achieved by removing all of the lymph nodes (known as full lymph node dissection) or a new procedure known as a sentinel node dissection. In this procedure, the surgeon injects a radioactive dye and/or a blue dye in the area around the tumor or around the nipple. The surgeon then finds the lymph nodes to which this dye travels and removes only those nodes. If there is cancer in one of these nodes with dye in it, then the rest of the nodes are removed. Otherwise, the nodes are left in place, which lowers the likelihood of developing complications such as arm swelling or pain after surgery. Studies have shown that women who have breast-sparing surgery require radiation therapy after surgery in order to reduce the risk that the cancer will come back in the breast.
The other type of surgery that is commonly performed in breast cancer is called a mastectomy. In this procedure, the entire breast is removed. This is usually done if the tumor is too large to remove without removing the entire breast, if the cancer is present in the skin of the breast (inflammatory breast cancer), or if the patient prefers this type of surgery. Again, the lymph nodes are sampled at the time of the mastectomy. Either a full axillary dissection may be performed or a sentinel lymph node dissection.
Radiation therapy (also called x-ray therapy, radiotherapy, or irradiation) uses high-energy rays to damage cancer cells and stop them from growing. Radiation is used after breast-conserving surgery to reduce the risk of the cancer returning in the breast. It may also be used after mastectomy if the cancer had spread to the lymph nodes. Radiation may come from an outside source or from radioactive materials placed directly in the breast. The patient receives external radiation treatments as an outpatient, usually five days a week for five or six weeks. At the end of that time, an extra "boost" of radiation is usually given to the treatment site. The boost may be either external (using electron beam therapy) or internal (using an implant). A short hospital stay may be required for implant radiation.
Local treatments remove cancerous cells from the breast and under arm lymph nodes. However, cancerous cells may have left the breast before the surgery and be present in other parts of the body. These cells can grow into a tumor in one of these other body locations months to years later in what is called a breast cancer recurrence. Unfortunately, if this occurs, the cancer is said to be “metastatic” and although it is treatable, it is no longer curable. In order to reduce the chance of this happening, systemic or whole body treatments are often used after surgery to try to kill any cancer cells that may have escaped from the breast prior to surgery. There are two primary kinds of adjuvant systemic treatments:
Chemotherapy drugs are medications that kill rapidly growing cells such as cancer cells. These drugs can be given either by mouth or intravenously. Chemotherapy medications are very powerful and can have many side effects. In general, chemotherapy is used for large tumors or for cancers that have spread to the under arm lymph nodes. Some types of cancer are also not sensitive to hormonal therapy and chemotherapy is usually used in these situations. Finally, younger women appear to benefit more from chemotherapy than older women. It is important to speak to a medical oncologist to find out if chemotherapy is recommended.
There are many different types of chemotherapy drugs used in the treatment of breast cancer. The most commonly used drugs are adriamycin, cytoxan and paclitaxel (Taxol), or docetaxel (Taxotere). Chemotherapy is usually given in “cycles”. One cycle of chemotherapy usually involves going to the oncologist’s office and receiving intravenous chemotherapy once every two to three weeks. This is usually repeated four to eight times, depending on the size of the tumor and lymph node status.
In recent years, new types of chemotherapy drugs have been developed that are targeted to special types of breast cancer. The most important of these so far is known as trastuzumab or Herceptin. This medication was developed specifically to treat cancers that have too much of a growth protein known as HER-2/neu. About 20 - 30 percent of breast cancers fall into this category, and treatment with this new medication has been shown to greatly reduce the risk of dying from this type of breast cancer. Many new medications are under development for other types of breast cancer.
Hormone therapy is used to prevent cancer cells from getting the hormones they need to grow. Hormonal therapy is only useful in treating tumors that have either estrogen receptors or progesterone receptors. These types of cancer are said to be hormone receptor positive or hormone responsive.
In post-menopausal women, the ovaries are no longer producing female hormones. However, these women still do have estrogen in their bodies. It comes from the adrenal glands, which are small glands that sit above the kidneys. The adrenals make male hormones that are transformed into female hormones in fat cells. This is one of the reasons that women with more fatty tissue have higher estrogen levels.
In women who have gone through menopause, there are two types of medicine which can prevent estrogen from getting to any cancer cells that may have escaped the breast before surgery. The medication tamoxifen is an estrogen receptor blocker, meaning that it prevents estrogen in the body from getting to the cancer cells. The other type of medications are called aromatase inhibitors (including Arimidex, Femara, and Aromasin). These medications stop the transformation of male hormones into female hormones. Both of these types of medications work well to prevent breast cancer from returning.
In pre-menopausal women, most of the estrogen in the body comes from the ovaries. The most common type of hormonal therapy in this group is tamoxifen, since this works to block estrogen no matter where it comes from. At times, the ovaries might also be removed to decrease the amount of estrogen in the body. However, given the increased side effects from this type of procedure, this is usually not recommended outside of a clinical trial.
Choice of treatment is often a complicated issue and must be individualized for each patient, with the consultation of a medication oncologist, a radiation oncologist and a surgeon.
How large was the breast cancer?
Had the cancer spread to the lymph nodes?
Has the cancer spread anywhere else?
Is my cancer estrogen receptor positive?
Is my cancer HER-2/neu positive?
What kind of surgery do you recommend and why?
Do you recommend radiation?
What kind of systemic treatments do you recommend and why?
What kind of symptoms should I be aware of?
What is my prognosis?
Editorial review provided by VeriMed Healthcare Network.
Examine Your Breasts Every Month Beginning At Age 20 (see your doctor for self breast exam instructions). Check for: new lump (painful or not), unusual thickening of tissue, discharge from the nipples, change in the skin of nipples or breasts, or different breast size or shape than before.
Have Your Doctor Examine Your Breasts Every Year Or Two Beginning At Age 30
Have A Mammogram Every Year After Age 40