Breast cancer is cancer that forms in the cells of the breasts.
After skin cancer, breast cancer 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.
Substantial support for breast cancer awareness and research funding has helped created advances in the diagnosis and treatment of breast cancer. Breast cancer survival rates have increased, and the number of deaths associated with this disease is steadily declining, largely due to factors such as earlier detection, a new personalized approach to treatment and a better understanding of the disease.
Signs and symptoms of breast cancer may include:
If you find a lump or other change in your breast — even if a recent mammogram was normal — make an appointment with your doctor for prompt evaluation.
Doctors know that breast cancer occurs when some breast cells begin to grow abnormally. These cells divide more rapidly than healthy cells do and continue to accumulate, forming a lump or mass. Cells may spread (metastasize) through your breast to your lymph nodes or to other parts of your body.
Breast cancer most often begins with cells in the milk-producing ducts (invasive ductal carcinoma). Breast cancer may also begin in 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. But it's not clear why some people who have no risk factors develop cancer, yet other people with risk factors never do. It's likely that breast cancer is caused by a complex interaction of your genetic makeup and your environment.
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 that can increase the likelihood of breast cancer have been identified. 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.
If you have a strong family history of breast cancer or other cancers, your doctor may recommend a blood test to help identify specific mutations in BRCA or other genes that are being passed through your family.
Consider asking your doctor for a referral to a genetic counselor, who can review your family health history. A genetic counselor can also discuss the benefits, risks and limitations of genetic testing to assist you with shared decision-making.
A breast cancer risk factor is anything that makes it more likely you'll get breast cancer. But having one or even several breast cancer risk factors doesn't necessarily mean you'll develop breast cancer. 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:
Breast cancer risk reduction for women with an average risk
Making changes in your daily life may help reduce your risk of breast cancer. Try to:
Breast cancer risk reduction for women with a high risk
If your doctor has assessed your family history and determined that you have other factors, such as a precancerous breast condition, that increase your risk of breast cancer, you may discuss options to reduce your risk, such as:
Tests and procedures used to diagnose breast cancer include:
Other tests and procedures may be used depending on your situation.
Staging breast cancer
Once your doctor has diagnosed your breast cancer, he or she works to establish the extent (stage) of your cancer. Your cancer's stage helps determine your prognosis and the best treatment options.
Complete information about your cancer's stage may not be available until after you undergo breast cancer surgery.
Tests and procedures used to stage breast cancer may include:
Not all women will need all of these tests and procedures. Your doctor selects the appropriate tests based on your specific circumstances and taking into account new symptoms you may be experiencing.
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; the presence of tumor markers, such as receptors for estrogen, progesterone and HER2; and proliferation factors.
Your doctor determines your breast cancer treatment options based on your type of breast cancer, its stage and grade, size, and whether the cancer cells are sensitive to hormones. Your doctor also considers your overall health and your own preferences.
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.
There are many options for breast cancer treatment, and you may feel overwhelmed as you make complex decisions about your treatment. Consider seeking a second opinion from a breast specialist in a breast center or clinic. Talk to other women who have faced the same decision.
Operations used to treat breast cancer include:
Most women with breast cancer in one breast will never develop cancer in the other breast. Discuss your breast cancer risk with your doctor, along with the benefits and risks of this procedure.
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. Discuss your options and preferences with your surgeon.
Consider a referral to a plastic surgeon before your breast cancer surgery. Your options may include reconstruction with a breast implant (silicone or water) or reconstruction using your own tissue. 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. Radiation therapy is typically done using a large machine that aims the energy beams at your body (external beam radiation). But radiation can also be done by placing radioactive material inside your body (brachytherapy).
External beam radiation of the whole breast is commonly used after a lumpectomy. Breast brachytherapy may be an option after a lumpectomy if you have a low risk of cancer recurrence.
Doctors may also recommend radiation therapy to the chest wall after a mastectomy for larger breast cancers or cancers that have spread to the lymph nodes.
Breast cancer radiation can last from three days to six weeks, depending on the treatment. A doctor who uses radiation to treat cancer (radiation oncologist) determines which treatment is best for you based on your situation, your cancer type and the location of your tumor.
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. Rarely, more-serious problems may occur, such as damage to the heart or lungs or, very rarely, second cancers in the treated area.
Chemotherapy uses drugs to destroy fast-growing cells, such as cancer cells. If your cancer has a high risk of returning or spreading to another part of your body, your doctor may recommend chemotherapy after surgery to decrease the chance that the cancer will recur.
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 try to control the cancer and 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. Rare side effects can include premature menopause, infertility (if premenopausal), damage to the heart and kidneys, nerve damage, and, very rarely, blood cell cancer.
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 or other treatments to decrease the chance of your cancer returning. If the cancer has already spread, hormone therapy may shrink and control it.
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 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.
Targeted therapy drugs that focus on other abnormalities within cancer cells are available. And targeted therapy is an active area of cancer research.
Your cancer cells may be tested to see whether you might benefit from targeted therapy drugs. Some medications are used after surgery to reduce the risk that the cancer will return. Others are used in cases of advanced breast cancer to slow the growth of the tumor.
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 that process.
Immunotherapy might be an option if you have triple-negative breast cancer, which means that the cancer cells don't have receptors for estrogen, progesterone or HER2. For triple-negative breast cancer, immunotherapy is combined with chemotherapy to treat advanced cancer that's spread to other parts of the body.
Palliative care is specialized medical care that focuses on providing relief from pain and other symptoms of a serious illness. Palliative care specialists work with you, your family and your other doctors to provide an extra layer of support that complements your ongoing care. 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.
Palliative care is provided by a team of doctors, nurses and other specially trained professionals. Palliative care teams aim to improve the quality of life for people with cancer and their families. This form of care is offered alongside curative or other treatments you may be receiving.