Breast cancer forms in the cells of the breasts. It is the most common cancer diagnosed in women in the United States. Breast cancer can occur in both men and women, but it's far more common in women. Early detection, prevention via genetic counseling, and a personalized approach to treatment has resulted in improved survival and lower deaths
Types of Breast Cancer
- Angiosarcoma - form in the lining of the blood and lymph vessels
- Ductal carcinoma in situ (DCIS) - cancer in milk duct cells, not invasive
- Inflammatory breast cancer - cancer cells block the lymphatic vessels in skin covering the breast, causing the characteristic red, swollen appearance of the breast.
- Invasive lobular carcinoma - milk-producing glands (lobules) of the breast become cancerous.
- Lobular carcinoma in situ (LCIS) - Lobular carcinoma in situ (LCIS) is an uncommon condition in which abnormal cells form in the milk glands (lobules) in the breast. LCIS isn't cancer.
- Male breast cancer - occurs in the breast tissues of men
- Paget's disease of the breast - starts on the nipple and extends to the dark circle of skin (areola) around the nipple.
- Recurrent breast cancer - breast cancer that returns after initial therapy
Signs and symptoms of breast cancer may include:
- A breast lump or thickening that feels different from the surrounding tissue
- Change in the size, shape or appearance of a breast
- Changes to the skin over the breast, such as dimpling
- A newly inverted nipple
- Peeling, scaling, crusting or flaking of the pigmented area of skin surrounding the nipple (areola) or breast skin
- Redness or pitting of the skin over your breast, like the skin of an orange
- Retraction of the tissue such as a dent or depression
Doctors know that breast cancer occurs when some breast cells begin to grow abnormally and more rapidly until they form a lump or mass. Cells may spread (metastasize) through your breast to your lymph nodes or to other parts of your body through blood vessels.
Breast cancer most often begins with cells in the milk-producing ducts (invasive ductal carcinoma) or the glandular tissue called lobules (invasive lobular carcinoma) or in other cells or tissue within the breast.
Researchers have identified hormonal, lifestyle and environmental factors that may increase your risk of breast cancer.
Inherited breast cancer
Doctors estimate that about 5 to 10 percent of breast cancers are linked to gene mutations passed through generations of a family.
A number of inherited mutated genes can increase the likelihood of breast cancer. The most well-known are breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2), both of which significantly increase the risk of both breast and ovarian cancer.
You might want to see a genetic counselor to discuss the benefits, risks and limitations of genetic testing to assist you with shared decision-making.
Many women who develop breast cancer have no known risk factors other than simply being women.
Factors that are associated with an increased risk of breast cancer include:
- Being female.
- Increasing age.
- A personal history of breast conditions. If you've had a breast biopsy that found lobular carcinoma in situ (LCIS) or atypical hyperplasia of the breast.
- A personal history of breast cancer. If you've had breast cancer in one breast, you have an increased risk of developing cancer in the other breast.
- A family history of breast cancer. If your mother, sister or daughter was diagnosed with breast cancer.
- Inherited genes that increase cancer risk. Gene mutations are referred to as BRCA1 and BRCA2 can greatly increase your risk of breast cancer and other cancers
- Radiation exposure. If you received radiation treatments to your chest as a child or young adult, your risk of breast cancer is increased.
- Being obese increases your risk of breast cancer.
- Beginning your period at a younger age. Beginning your period before age 12 increases your risk of breast cancer.
- Beginning menopause at an older age. If you began menopause at an older age, you're more likely to develop breast cancer.
- Having your first child at an older age. After age 30 may have an increased risk of breast cancer.
- Having never been pregnant. Women who have never been pregnant have a greater risk of breast cancer.
- Postmenopausal hormone therapy. Women who take hormone therapy such as estrogen and progesterone for menopause have an increased risk of breast cancer.
- Drinking alcohol. Drinking alcohol increases the risk of breast cancer.
Making changes in your daily life may help reduce your risk of breast cancer. Try to:
- Ask your doctor about breast cancer screening.
- Become familiar with your breasts through breast self-exam for breast awareness. Women may choose to become familiar with their breasts by occasionally inspecting their breasts during a breast self-exam for breast awareness.
- Drink alcohol in moderation, if at all.
- Exercise most days of the week. Aim for at least 30 minutes of exercise on most days of the week.
- Limit postmenopausal hormone therapy. To reduce the risk of breast cancer, use the lowest dose of hormone therapy possible for the shortest amount of time.
- Maintain a healthy weight. If your weight is healthy, work to maintain that weight.
- Choose a healthy diet. Women who eat a Mediterranean diet supplemented with extra-virgin olive oil and mixed nuts may have a reduced risk of breast cancer.
Breast cancer risk reduction for women with a high risk
- Preventive medications (chemoprevention). Estrogen-blocking medications, such as selective estrogen receptor modulators and aromatase inhibitors, reduce the risk of breast cancer in women with a high risk of the disease.
- Preventive surgery. Women with a very high risk of breast cancer may choose to have their healthy breasts surgically removed (prophylactic mastectomy). They may also choose to have their healthy ovaries removed (prophylactic oophorectomy) to reduce the risk of both breast cancer and ovarian cancer.
Diagnosing breast cancer
Tests and procedures used to diagnose breast cancer include:
- Breast exam. Your doctor will check both of your breasts and lymph nodes in your armpit, feeling for any lumps or other abnormalities.
- A mammogram is an X-ray of the breast.
- Breast ultrasound. This technique uses sound waves to produce images of structures deep within the body and can tell a fluid filled mass versus a solid mass.
- Removing a sample of breast cells for testing (biopsy). A biopsy is the only definitive way to make a diagnosis of breast cancer. A specialized needle device guided by X-ray or another imaging test is used to extract a core of tissue.
- Breast magnetic resonance imaging (MRI). An MRI machine uses a magnet and radio waves to create pictures of the interior of your breast. Before a breast MRI, you receive an injection of dye. No radiation is used.
Other tests and procedures may be used depending on your situation.
Staging breast cancer
Tests and procedures used to stage breast cancer may include:
- Surgery and size of mass, positive lymph nodes
- Blood tests, such as a complete blood count
- Mammogram of the other breast to look for signs of cancer
- Breast MRI
- Bone scan
- Computerized tomography (CT) scan
- Positron emission tomography (PET) scan
Breast cancer stages range from 0 to IV with 0 indicating cancer that is noninvasive or contained within the milk ducts. Stage IV breast cancer, also called metastatic breast cancer, indicates cancer that has spread to other areas of the body.
Breast cancer staging also takes into account your cancer's grade, which is how abnormal the cells appear under microscope; the presence of tumor markers, such as receptors for estrogen, progesterone and HER2; and proliferation factors.
Most women undergo surgery for breast cancer and many also receive additional treatment after surgery, such as chemotherapy, hormone therapy or radiation. Chemotherapy might also be used before surgery in certain situations.
Breast cancer surgery
Operations used to treat breast cancer include:
- Removing the breast cancer (lumpectomy). During a lumpectomy, or breast-conserving surgery or wide local excision, the surgeon removes the tumor and a small margin of surrounding healthy tissue.
- Removing the entire breast (mastectomy). A mastectomy is an operation to remove all of your breast tissue- the lobules, ducts, fatty tissue and some skin, including the nipple and areola (total or simple mastectomy).
Skin-sparing mastectomy and nipple-sparing mastectomy are increasingly common operations for breast cancer.
- Removing a limited number of lymph nodes (sentinel node biopsy). If no cancer is found in the lymph nodes closest to your breasts, the chance of finding cancer in any of the remaining lymph nodes is small and no other nodes need to be removed.
- Removing several lymph nodes (axillary lymph node dissection). If cancer is found in the sentinel lymph nodes, your surgeon will discuss with you the role of removing additional lymph nodes in your armpit.
- Removing both breasts. If you have an increased risk of cancer in the other breast such as genetics
Complications of breast cancer surgery depend on the procedures you choose. Breast cancer surgery carries a risk of pain, bleeding, infection and arm swelling (lymphedema).
You may choose to have breast reconstruction after surgery. Consult a plastic surgeon for reconstruction. These operations can be performed at the time of your mastectomy or at a later date.
Radiation therapy uses high-powered beams of energy, such as X-rays and protons, to kill cancer cells. External beam radiation or brachytherapy, which means the radioactive material is place in or near the tumor.
Large tumors or positive lymph nodes are two reasons to have radiation.
Side effects of radiation therapy include fatigue and a red, sunburn-like rash where the radiation is aimed. Breast tissue may also appear swollen or more firm.
Chemotherapy uses drugs to destroy fast-growing cancer and is used if your cancer has a high risk of returning or spreading to another part of your body.
Chemotherapy is sometimes given before surgery in women with larger breast tumors. The goal is to shrink a tumor to a size that makes it easier to remove with surgery.
Chemotherapy is also used in women whose cancer has already spread to other parts of the body. Chemotherapy may be recommended to decrease any symptoms the cancer is causing.
Chemotherapy side effects depend on the drugs you receive. Common side effects include hair loss, nausea, vomiting, fatigue and an increased risk of developing an infection. Medications can reduce the severity of these side effects
Hormone therapy — perhaps more properly termed hormone-blocking therapy — is used to treat breast cancers that are sensitive to hormones. Doctors refer to these cancers as estrogen receptor positive (ER positive) and progesterone receptor positive (PR positive) cancers.
Hormone therapy can be used before or after surgery to decrease the chance of your cancer returning.
Treatments that can be used in hormone therapy include:
- Medications that block hormones from attaching to cancer cells (selective estrogen receptor modulators)
- Medications that stop the body from making estrogen after menopause (aromatase inhibitors)
- Surgery or medications to stop hormone production in the ovaries
Hormone therapy side effects depend on your specific treatment, but may include hot flashes, night sweats and vaginal dryness. More serious side effects include a risk of bone thinning and blood clots.
Targeted therapy drugs
Targeted drug treatments attack specific abnormalities within cancer cells. As an example, several targeted therapy drugs focus on a protein that some breast cancer cells overproduce called human epidermal growth factor receptor 2 (HER2). The protein helps breast cancer cells grow and survive. By targeting cells that make too much HER2, the drugs can damage cancer cells while sparing healthy cells.
Immunotherapy uses your immune system to fight cancer. Your body's disease-fighting immune system may not attack your cancer because the cancer cells produce proteins that blind the immune system cells. Immunotherapy works by interfering with those blinding proteins.
Immunotherapy is an option for triple-negative breast cancer, which means that the cancer cells don't have receptors for estrogen, progesterone or HER2. Immunotherapy is combined with chemotherapy to treat advanced cancer that's spread to other parts of the body.
Supportive (palliative) care
Palliative care is specialized medical care that focuses on providing relief from pain and other symptoms of a serious illness.. Palliative care can be used while undergoing other aggressive treatments, such as surgery, chemotherapy or radiation therapy.
When palliative care is used along with all of the other appropriate treatments, people with cancer may feel better and live longer.