Breast Cancer Basics



Breast Cancer Basics

|What is breast cancer? |How is breast cancer treated? |

|Risk factors |What is bone metastasis? |

|How is breast cancer diagnosed? |Glossary |

|How does breast cancer progress? |[pic] |

What is breast cancer?

After skin cancer, breast cancer is the most common type of cancer among women in the United States. According to the National Cancer Institute's SEER (Surveillance, Epidemiology and End Results) database, approximately 211,000 women and 1,300 men will develop breast cancer in 2003. It is the second leading cause of cancer mortality in women with an estimated 40,000 deaths in 2002. To more fully understand this disease and its treatments, it is helpful to know the basic anatomy of a breast, and about how cancers, in general, develop.

The human breast is divided into about 20 sections, which are called lobes. Within each lobe, there are many smaller divisions called lobules, where milk is produced. Thin tubes called ducts link the lobes and lobules to the nipple. All these structures are surrounded by fatty tissue. Breasts also contain blood vessels and lymph vessels. The lymph vessels carry lymph or lymphatic fluid, which is a clear fluid containing cells of the immune system that help fight infection and other diseases. The lymph vessels carry the lymph to the lymph nodes which are rounded masses of lymphatic tissue surrounded by a capsule of connective tissue. Lymph nodes, which filter the lymph, are found in many parts of the body, including in clusters under the arm, above the collarbone, and in the chest. Click here for a good diagram of these structures

Breast cancer, like other cancers, develops when abnormal cells begin to grow and divide uncontrollably. The excess cells form a mass of tissue called a malignant or cancerous tumor. (Sometimes normal cells may grow rapidly and form a benign or non-cancerous tumor). As the tumor enlarges, cells within it can break away from their original sites. These cancer cells can travel through the blood or lymph, invading and damaging other tissues and organs. Breast cancer almost always develops in lobular or ductal tissue. Cancerous cells that spread outside of the breast are often found in the lymph nodes under the arm, called the axillary lymph nodes.

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Risk factors

Much research has focused on factors that put women at risk of developing breast cancer. The most important risk factor is age. Breast cancer is uncommon in women younger than 35. Most cases develop in women older than 50, and the risk increases as women pass 60, 70 and 80. White women develop breast cancer more often than African American or Asian women. There are several other risk factors, although it is important to note that for most women who develop breast cancer, the only risk factor is increased age.

• Personal medical history: Women who have had breast cancer in one breast are at greater risk of developing the disease in the other breast.

• Family medical history: Women whose mothers, sisters, or daughters have had breast cancer face increased risk, especially if their relatives had breast cancer while young. However, it is estimated that only about 5 percent of women have a genetic predisposition to breast cancer.

• Some prior breast changes: A diagnosis of atypical hyperplasia or lobular carcinoma in situ (LCIS) increases risk.

• Genetic factors: Testing in families where many women have had breast cancer sometimes shows changes in specific genes. These changes increase the risk of developing breast cancer. Testing for these gene alterations (called BRCA-1 and BRCA-2) is not routinely done as part of breast cancer screening for average woman but is sometimes done in women with strong family histories.

Research suggests other factors may play a role:

• Exposure to hormones: In general, the longer women are exposed to estrogen, the more likely they may be to develop breast cancer. Women who began menstruating before age 12 or who went through menopause after age 55 may be at increased risk. The same may be true for women who never had children and those who are taking or who recently took hormone replacement therapy for five years or longer.

• First child after age 30: Women who have first children later in life may have a greater chance of developing the disease than those who have first children earlier.

• Dense breasts: Since breast cancer most often develops in lobular or ductal tissue, women with a high proportion of this kind of dense tissue may be at greater risk.

• Radiation therapy: Women whose breasts were exposed to radiation during radiation therapy before age 30 are at increased risk of developing breast cancer later in life.

• Alcohol use: Some studies show a slightly higher risk of breast cancer in women who consume more than one alcoholic drink a day.

• Obesity: Women who are obese, particularly after menopause, may be at higher risk.

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How is breast cancer diagnosed?

Women should talk to their healthcare providers about their risk factors and determine how often they should be screened for breast cancer. Screening tests include:

• Breast self-exams (BSE): Many women check their breasts each month, looking and feeling for lumps or other changes. Though scientific evidence for the effectiveness of breast self-exams is mixed at best, many healthcare providers and patient advocacy groups recommend regular self-exams.

• Clinical breast exams: Healthcare providers may periodically check a woman's breasts and under her arms for lumps or other abnormalities. These checks are often part of a regular physical exam.

• Mammograms: X-rays of the breast can detect changes in women who have no other signs of breast cancer. Mammograms can detect breast lumps before they can be felt and can also detect small deposits of calcium that may be an early sign of cancer. They are very valuable in the early detection of breast cancer. Studies have shown that regular mammogram screening saves lives. Mammograms, however, are not without limitations. They sometimes miss cancer, or identify changes in the breast that are not cancer. Still, many healthcare experts recommend that women older than 40 years of age have mammograms every one to two years. The American Cancer Society recommends the test be done yearly after age 40.

When breast cancer first develops, women may not notice any symptoms. As cancer progresses, however, it can cause changes in and around the breast, including:

• A lump or thickening in or near the breast or under the arm

• Change in the size or shape of the breast

• Discharge from the nipple, or tenderness at the nipple

• Nipple pulled back into the breast

• Ridges, dimpling or pitting in the breast (skin looks like an orange peel)

• Change in the skin of the breast, nipple, or the colored area around the nipple, called the areola. Examples of changes are redness, warmth, ulceration, scaly or swollen skin.

Most often, these changes are not cancer, but it is important for women to watch for them and to check with a doctor if they notice a change. The doctor may order a number of diagnostic tests to determine the cause of the symptom:

• Physical exam and medical history: The doctor will most likely give a patient a thorough examination and ask detailed questions about the patient's family's health history as well as his or her own.

• Clinical breast exam: Doctors can tell quite a bit about the nature of a lump by physically examining its size, texture, and the way it moves.

• Mammography: The doctor may order X-rays of the breast to evaluate lumps or changes.

• Ultrasonography: Sometimes used in combination with mammography, ultrasonography uses high-frequency sound waves to determine the physical nature of a lump. Ultrasound can help distinguish the difference between a cyst, which is usually not cancer, and a solid mass, which may or may not be cancer.

Based on results of these tests, the doctor may decide that no further exams are needed and treatment is not necessary. He or she may simply check the patient regularly for signs of change. If the results of the test don't rule out cancer, the doctor may order a biopsy, in which fluid or tissue is removed from the breast and examined under a microscope. A biopsy is required for a definitive diagnosis of breast cancer. Doctors may refer patients to breast surgeons for these procedures.

There are two main types of biopsies: needle biopsy and open surgical biopsy. The type of biopsy a patient and doctor choose depends largely on the nature and location of the cells or tissue to be sampled and the patient's health and preference.

• Needle biopsy: This method is sometimes used first because it is fast, relatively simple, and can usually be done in an outpatient setting. In a fine needle aspiration, a thin, hollow needle is used to remove fluid or cells from a breast lump or tissue. A core needle biopsy uses a wider needle to take a larger piece of a lump or tissue.

• Open surgical biopsy: This method removes a lump or abnormal tissue from the breast. It can be done in the hospital or in an outpatient setting. Women are often able to go home the same day. Excisional biopsy removes the entire lump or suspicious tissue. Although its primary purpose is to diagnose cancer, an excisional biopsy can also be a surgical treatment for cancer. Incisional biopsy removes part of a lump, and is often the choice for women with more advanced cancer whose tumors are too large to be removed by excisional biopsy.

If the result of a biopsy shows cancer is present, doctors may order a hormone receptor test to determine whether hormones help the cancer grow. If results show that the cancer does need hormones to grow, then doctors and patients may consider hormonal therapy, which deprives the cancer cells of the necessary hormones. More information on this therapy is provided in the treatment section.

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How does breast cancer progress?

There are several types of breast cancer. They are distinguished by where the cancer originated and by whether or not it has spread. The most common type is ductal carcinoma, which begins in the lining of the tubes that carry milk to the nipple. Lobular carcinoma begins in the lobules, where milk is produced.

Breast cancer can also be in situ or invasive. In situ breast cancers are small nests of cancer cells or abnormal cells that are confined only to the duct or the lobule. No spread outside the duct or lobule has occurred. This condition may increase the risk that a woman eventually will develop invasive breast cancer. It is most often diagnosed with a biopsy after an abnormality was noted on a screening mammogram.

Invasive breast cancer occurs when ductal or lobular cancers spread into nearby breast tissue or into the lymph nodes under the arm. This does not mean that the cancer has metastasized. Metastasis occurs when cancer cells break off from the primary tumor and move through the bloodstream or lymph system to other more distant organs.

As with other kinds of cancer, doctors use a rating scale to describe the seriousness, or stages, of breast cancer. There are five stages: 0, I, II, III and IV. In general, the lower the stage, the better the chances for a cure and long-term survival. The stages are based on the size of the tumor, how the cancer affects the underarm lymph nodes, and whether the cancer has metastasized to distant parts of the body. Treatment during each stage depends on a patient's individual situation. Some common treatments are listed here, but it's important to note that not every person needs the same kind of treatment.

Stage 0

This stage refers to carcinoma in situ as described above which may also be called noninvasive carcinoma.

• Ductal carcinoma in situ, or DCIS, refers to cancer cells in the lining of a duct. Though the cancer cells have not spread beyond the duct, in some cases DCIS can progress to invasive breast cancer. This stage is commonly treated with breast conserving surgery (i.e. lumpectomy) and radiation. Mastectomy - removal of the breast - without radiation is also an option. Studies are ongoing to determine if the post operative radiation is necessary and if the hormonal therapy, tamoxifen, would be of benefit.

• Lobular carcinoma in situ, or LCIS, refers to a cluster of abnormal cells in the lining of a lobule. Unlike DCIS, these cells are not actually cancer cells and it is not known if they ever transform into cancer cells. However, women with LCIS are at increased risk of developing invasive breast cancer. Therefore, after having a biopsy, most women with LCIS need no other surgical treatment or radiation. Tamoxifen is usually considered as a therapy to prevent future breast cancer. Bilateral mastectomy - or removal of both breasts - has been considered as a preventative therapy. However, according to the National Cancer Institute, most breast surgeons now consider this an overly aggressive approach.

Stage I and Stage II

In these early stages, the cancer cells are confined to the breast and lymph nodes under the arm.

• In stage I, tumors are up to 2 cm (or about ¾ inch) across and cancer cells have not spread outside of the breast.

• In stage II, one of three situations is present: the tumor is less than 2 cm across and the cancer has spread to the axillary lymph nodes under the arm; the tumor is between 2 cm and 5 cm (about 2 inches) and may or may not have spread to the axillary lymph nodes; the tumor is larger than 5 cm across but cancer cells have not spread to the axillary lymph nodes.

These stages of breast cancer are usually treated with either breast-conserving surgery followed by radiation therapy or a mastectomy, with or without breast reconstruction later. Radiation may be recommended after mastectomy is if many axillary lymph nodes are positive. Additionally, treatment may include chemotherapy, hormonal therapy, or both. This is dependent upon factors such as whether the cancer has spread to the axillary nodes, whether the hormone receptors are positive (see treatment section) and the age and general health of the patient. Some women may qualify for clinical trials that test new therapies. Click here for a listing of clinical trials at the National Cancer Institute

Stage III

• This stage, also called locally advanced cancer, is characterized in three ways: the tumor radius is more than 5 centimeters (about 2 inches) and the cancer has spread to the axillary lymph nodes; the cancer in the axillary lymph nodes is extensive regardless of the size of the tumor; the cancer has spread to lymph nodes in or near the breastbone or to other tissues near the breast.

• Inflammatory breast cancer is a type of locally advanced breast cancer in which the breast looks red and swollen because cancer cells block the lymph vessels in the skin.

Stage III breast cancer is often treated with chemotherapy first and then followed by surgery radiation therapy, and hormonal therapy. Again, the choice of treatments depends upon the hormone receptor status and the age and general health of the patient. Again, participation in clinical trials may be an option.

Stage IV

• Stage IV breast cancer has metastasized. That is, the cancer has spread beyond the breast and axillary lymph nodes to other parts of the body.

Treatment usually includes chemotherapy, which may be followed by either breast-conserving surgery or total mastectomy and radiation therapy. Women may undergo additional chemotherapy and hormonal therapy. Some women may receive biologic therapies as well (see treatment section). Women in this stage may also be candidates for clinical trials of new anti-cancer drugs, new drug combinations, and new approaches to treatment.

Five-year survival rates are a common measure for cancer patients. It's important to remember that these numbers are averages and don't apply to individuals. According to the American Cancer Society, 97 percent of patients with localized breast cancers survive at least five years. If the breast cancer has spread regionally but has not invaded more distant organs, the five-year survival rate is 78 percent. The five-year survival rate for patients whose breast cancer has metastasized to distant organs is 23 percent.

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How is breast cancer treated?

Standard treatments for breast cancer can be local or systemic. Local treatments, such as surgery or radiation therapy, remove or destroy cancer in the breast and surrounding areas. Systemic treatments, such as chemotherapy or hormonal therapy, destroy or control cancer throughout the body. Breast cancer patients often have both kinds of treatment, sometimes one after the other.

Surgery

Surgery is the most common treatment for breast cancer. Surgeons use several different procedures, depending on a patient’s individual condition.

• Breast-conserving surgeries remove the breast cancer, but not the breast itself. These surgeries include lumpectomy, in which the surgeon removes the tumor and some tissue surrounding it; and segmental mastectomy, in which the surgeon removes the cancer and a larger area of normal breast tissue nearby. In segmental mastectomy, occasionally some lymph nodes under the arm and part of the lining over the chest muscles below the tumor may also be removed.

• Mastectomy is an operation that removes the breast, or as much of the breast as possible. In a total mastectomy, the surgeon removes the entire breast and sometimes some lymph nodes under the arm. In a modified radical mastectomy, the entire breast, most of the lymph nodes, and often some of the lining of the chest muscles are removed. In the rarely-used radical mastectomy, the surgeon removes the breast, chest muscles, lymph nodes under the arm, and some additional fat and skin.

• Axillary lymph node dissection is a surgical procedure that removes some lymph nodes under the arm in order to examine them to help determine whether cancer cells have entered the lymphatic system.

• Sentinel lymph node biopsy: This procedure is the surgical removal of the first lymph node to which the cancer is likely to spread. Doctors identify this lymph node by injecting a radioactive substance or a blue dye near the tumor. The substance or dye flows through the lymph ducts to the lymph nodes. The first lymph node to receive the substance or dye is removed for biopsy, and the tissue is examined under a microscope for cancer cells. If cancer cells are not found, it may not be necessary to remove more lymph nodes. After the sentinel lymph node biopsy is complete, surgeons remove the breast tumor. This procedure was developed as an alternative to the more invasive axillary lymph node dissection. The decision to use this technique versus an axillary lymph node dissection is made on an individual basis.

Radiation therapy

Radiation therapy, also called radiotherapy, uses high-energy rays to kill cancer cells. Patients who have had surgery, especially those who have had breast-conserving procedures, sometimes undergo radiation therapy to destroy any remaining cancer cells. Some may have radiation therapy before surgery to destroy cancer cells and shrink tumors.

• External radiation therapy uses rays from a machine directed at the breast.

• Implant radiation therapy involves a surgeon implanting radioactive material encased in thin plastic tubes directly into the breast.

Chemotherapy

Chemotherapy is the use of medications, often in combination, to stop the growth of cancer cells either by killing them or by preventing them from dividing. Because the drugs also affect normal cells, they can cause long-term side effects and some short-term effects, such as hair loss, nausea and drop in blood counts. Chemotherapy is usually taken orally or by injection.

Cancer specialists work with patients to determine which combination of the more than 30 drugs available will work best for them. The most effective drugs will work alone, but often combinations of drugs are necessary. Some of the most frequently used chemotherapy combinations are:

• Cyclophosphamide (Cytoxan) and doxorubicin (Adriamycin), a combination called AC.

• Cyclophosphamide (Cytoxan), methotrexate (Methotrexate), and 5-fluorouracil (Adrucil), called CMF.

• Cyclophosphamide (Cytoxan), doxorubicin (Adriamycin), and 5-fluorouracil (Adrucil) called either CAF or FAC.

• Cyclophosphamide (Cytoxan), doxorubicin (Adriamycin), and paclitaxel (Taxol) referred to as AC–Taxol.

Some other chemotherapy medications used in breast cancer are docetaxel (Taxotere), capecitabine (Xeloda), and epirubicin (Ellence).

Hormonal therapy

Some types of breast cancer cells have receptors for the hormones estrogen and progesterone. Receptors are protein molecules that are present on the surface of cells. Specific molecules attach to the receptor and then affect the function of the cell. In this case, two different receptors on the surface of certain breast cancer cells bind the hormones estrogen and progesterone. In these types of breast cancer, the estrogen and/or progesterone bind to the receptor(s) and stimulate the growth of the cancer cells.

Tests can be performed on the breast cancer biopsy that will determine if the cancer is positive for estrogen receptor, progesterone receptor or both. If either or both of the tests are positive, then hormonal therapy is usually considered. Hormonal therapies are medications that either reduce the body’s production of hormones or block the receptor’s ability to bind the hormone. Tamoxifen (Nolvadex) is the therapy that has been used the longest. Additional therapies include toremifene (Fareston), anastrozole (Arimidex), letrozole (Femara), exemestane (Aromasin), and gosereline (Zoladex implant). Raloxifene, (Evista) is a marketed drug for osteoporosis that is being studied as a possible hormonal therapy in breast cancer.

These drugs are not without side effects. Tamoxifen, for example, can increase the chance of developing endometrial cancer (cancer of the uterus), so women taking tamoxifen should have regular evaluations by a gynecologist.

Biological therapy

Also called immunotherapy, this approach attempts to marshal the body’s natural defenses against cancer. Unlike chemotherapy, which attacks all the bodies cells, biologic therapies target specific cells and, in general, have fewer side effects. One biologic therapy, trastuzamab (Herceptin) is approved for the treatment of metastatic breast cancer. This medication is a protein that binds to a receptor on the surface of some types of breast cancer. The receptor is called human epidermal growth factor receptor-2 (HER-2). By blocking this receptor on cancer cells, trastuzumab blocks the effect of human epidermal growth factor which helps to stop or slow down the cancer’s growth.

Future treatments

New drugs and therapies for breast cancer are being tested in clinical trials. Click here to learn more about clinical trials listed at the National Cancer Institute

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What is bone metastasis?

 

When cancer cells break off from the original tumor and spread to other parts of the body, doctors say the disease has metastasized. One of the most common places cancer spreads to is the bones, a condition called bone metastasis. This is not the same as primary bone cancer, a form of the disease that begins in the bone. But it is a serious complication that can weaken bones, cause pain and make it difficult for a person to continue the activities he or she enjoys.

 

Whether or not cancer spreads to the bones depends in large part on how much cancer is present and where the original cancer originated. Bone metastasis is not unusual for people with all advanced cancers. But it is more likely to happen in certain types of cancer, including breast cancer. About three out of four women with advanced breast cancer eventually develop bone metastases.

 

Sometimes doctors find bone metastasis when they discover the original cancer. At other times, they find it months or years later, often during follow-up tests. To find bone metastasis, doctors use imaging tests, such as X-rays, bone scans, computed tomography (CT or "cat" scans) and magnetic resonance imaging (MRI). They also use blood tests to look for high levels of substances that are released by cancer cells or by damaged bone. If they suspect a bone metastasis, doctors may request a biopsy to take a tiny amount of tissue for study under a microscope.

 

• INTERACTIVE: View a bone mets slide show

• MESSAGE BOARDS: Join a bone mets discussion

 

Symptoms of bone metastasis include:

 

• Pain in a bone: This is often the first symptom of bone metastasis. The pain may come and go and feel worse at night. 

• Broken bones (fractures): Most often fractures related to bone metastasis occur in the bones of the arms and legs and in the spine.

• Back pain and numbness in the legs: Cancer that spreads to the spine can put pressure on the spinal cord. This causes pain, and can cause numbness and even paralysis in the legs.

Loss of appetite, nausea, thirst and extreme fatigue: When cancer moves to the bones, they begin to release calcium. This causes the level of the mineral in the blood to rise. The condition, called hypercalcemia, can make people feel nauseated, thirsty and very tired. Doctors commonly treat bone metastasis by treating the underlying cancer, such as with chemotherapy. But there are also treatments that both target bone metastasis specifically and that combat its symptoms:

 

• Bisphosphonates: Bisphosphonates are a class of drugs that treat certain bone disorders (such as osteoporosis), including some related to cancer. They work by suppressing the cells that tear down bone. These drugs can help reduce bone pain and lower the risk of broken bones. Recent research shows bisphosphonates may also slow or prevent bone metastasis. The U.S. Food and Drug Administration has approved two bisphosphonates for people with breast cancer bone metastases: pamidronate (Aredia) and zoledronic acid (Zometa).

• Radiation treatments: If cancer has spread to one or two bones, doctors may use external radiation to kill the cancer cells and relieve the pain of bone metastasis. If the cancer has spread to several bones, doctors may try radiopharmaceuticals (also known as radioimmunotherapy). These are radioactive substances doctors inject into a vein. They travel to and settle in the bone, where the radiation kills cancer cells and helps relieve pain.

• Surgery: To relieve the symptoms of bone metastasis, doctors sometimes use surgery that stabilizes weakened bones with metal rods or other devices. This makes it less likely that the bones will break. If bones are already broken, surgery can ease the pain of bone metastasis and help people continue to perform their daily activities.

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