The breasts are connected to lymphatic vessels, which drain into a network of lymph nodes in the armpit (axillary lymph nodes). Cancer cells can sometimes enter these nodes and spread to other parts of the body.
A health professional will remove a small piece of tissue from the affected area and send it to a lab for testing. This is called a biopsy.
Breast cancer occurs when cells grow uncontrollably and form a tumour. It is the most common cancer in women worldwide, affecting both pre- and post-menopausal women. The most common type of breast cancer is ductal carcinoma, which develops in the tubes (ducts) that carry milk from glandular tissue to the nipple. Other types of breast cancer include lobular carcinoma, inflammatory breast cancer and mucinous carcinoma.
Most cancers are malignant, but a small percentage of them are benign (non-cancerous). Benign tumors do not spread to other sites in the body and are unlikely to affect surrounding structures or cause any symptoms. Cancerous tumours, on the other hand, can spread to distant parts of the body via the blood or lymphatic system, causing symptoms and leading to death.
Inherited gene mutations increase your risk of getting certain types of cancer. Mutations can change how your genes work or affect their structure and function. They may also cause your cells to grow faster or not die when they should. Only a small number of cancers are caused by inherited gene mutations. These include BRCA1 and BRCA2 mutations, which can increase your risk of developing breast cancer and ovarian cancer.
The information in this PDQ patient summary is based on scientific evidence from medical and health care professionals. It is reviewed and updated regularly by experts at the PDQ Adult Treatment Editorial Board. This summary was last updated in August 2022. The PDQ patient summaries are written by doctors and lay people working together to help patients make sense of the complex medical information about diseases and conditions. The Editorial Board is made up of specialists from many different fields who are experts in their area. They write the summaries with the help of a Patient Review Editor, who checks the facts and makes sure the information is accurate.
Many women who find growths during breast self-exams are alarmed, but most of these are not cancerous. Benign tumors do not grow rapidly, and they do not spread. They can occur anywhere in the body and can look like cysts or solid masses. Benign tumors do not usually come back after they are removed.
The most common benign tumors are called adenomas, which start in the epithelial tissue that covers glands and other internal organs. These include polyps in the colon and growths on the adrenal and pituitary glands. Adenomas do not usually cause any symptoms, but they can become malignant if they are left untreated.
Other types of benign tumors are fibromas, which grow in fibrous connective tissues such as muscle and fat. These can appear in the uterus, the lungs, and the bones. They can cause pain, swelling, or bleeding. Benign tumors can be treated with hormone therapy, surgery, radiation or chemotherapy.
Sometimes doctors recommend a watch-and-wait approach with benign tumors. If they are small and do not cause any symptoms, this may be appropriate. Other times, physicians may want to treat the tumor as soon as it causes side effects or it grows too big.
Some benign tumors need to be removed before they can cause serious problems. For example, if a fibroma forms on the brain it can press against nerves and cause a loss of balance or hearing. This type of tumor is often removed surgically and followed by speech therapy or physiotherapy to help with the problems it has caused. Other tumors can be removed by aspiration (a thin tube inserted into the lesion to remove fluid or cells). This is usually followed by biopsy.
There are many genes in the body that help to control cell growth. Mutations (changes) in these genes can cause cancer cells to grow and spread. Gene mutations can either be inherited or acquired. One or two acquired mutations are unlikely to cause cancer, but a build-up of these changes over time could increase the chance of developing cancer. Mutations that are inherited increase the chance of getting cancer because they are passed on by your parents in your DNA.
Some gene mutations are related to breast cancer, for example changes in the BRCA1 and BRCA2 genes. Mutations in these genes raise a woman’s risk of developing cancer, especially breast and ovarian cancer, at a younger age than women without them.
Other inherited gene mutations that increase breast cancer risk are mutations in the TP53 and PTEN genes. These genes normally help to prevent the growth of cells with damaged DNA. Inherited mutations in these genes increase a woman’s risk of developing breast cancer and other tumours, such as leukemia and brain tumours.
There are also other inherited gene mutations that increase the risk of cancer, such as the ATM gene. This gene helps to fix mistakes that are made when DNA copies itself during cell division. Inherited mutations in the ATM gene are associated with an increased risk of breast cancer and cancer of the pancreas and ovary.
Hormones are chemical messengers that control many different parts of the body. Some breast cancer cells use hormones like estrogen and progesterone to grow, and they have receptors on their surface that attract those hormones. Hormone therapy lowers or blocks the hormones, and that keeps cancer cells from getting what they need to grow.
Medications used to treat hormone-sensitive cancers can be taken as tablets, usually once a day, and you should take them at the same time each day. You may also need to take other medicines that help control side effects. You will need to continue taking your hormone treatment for as long as your doctor tells you.
You can have hormone therapy before or after surgery to reduce the risk of your cancer returning (adjuvant therapy). It is also used in combination with chemotherapy and radiation therapy for early-stage breast cancer, and it can be given with tamoxifen to treat metastatic or advanced breast cancer.
The hormones oestrogen and progesterone pass through the bloodstream and attach to the cancer cells’ receptors. That signals the cancer cells to grow. Some types of breast cancer cells are oestrogen receptor positive, and about 80% of all breast cancers are oestrogen receptor positive. Hormonal therapy stops or decreases the amount of oestrogen in the body and so stops those cancer cells from growing. Some treatments for hormone-sensitive cancers include surgery, chemotherapy and radiotherapy, and others involve removing your ovaries along with the cancerous tumours. This causes a rapid menopause and you will need to take medicines like tamoxifen or toremifene (also known as aromatase inhibitors) to manage the symptoms, which can include hot flushes and sweating.
Most breast cancers are found with screening mammograms, before symptoms appear. Some types of breast cancer are easier to treat if they’re caught early, when they’re smaller and less likely to spread.
Symptoms may include pain in one or both breasts, a lump or change in the shape of your breast. Your skin may feel different or look dimpled, puckered or scaly and your nipple might discharge fluid.
X-rays are a type of electromagnetic radiation that can pass through your body and produce shadow-like images of bones and some organs. The radiation used in X-rays is safe and does not cause harm to you. Before undergoing an X-ray, your healthcare team will weigh the benefits and risks. They may recommend a CT scan or fluoroscopy instead of an X-ray for diagnosing your condition.
These tests are able to detect many cancers in the early stages when they are smaller and before they can be felt as a lump. They can also find cancers that have spread to nearby tissue and lymph nodes (small, bean-shaped organs that help fight infection).
A mammogram is an X-ray picture of your breast. It can be used to check for different types of breast cancer, including invasive (infiltrating) ductal carcinoma, which starts in your milk ducts and spreads into surrounding breast tissue. It can also detect microcalcifications, which are tiny deposits of calcium that sometimes indicate the presence of a tumor.
You should always tell your doctor if you notice any unusual changes to your breasts. These can include a lump or thickening that doesn’t go away. Changes in the texture of your skin on your breast or nipple, such as reddening, puckered or dimpling, or a rash that looks like the peel of an orange. Swelling in your armpit, which can be a sign of breast cancer that has spread to lymph nodes in the area.
Your doctor can also order a complete blood count (CBC), which measures the number of each type of cell in your body, and a blood chemistry test. These help your doctor look for other health problems that could be causing the symptoms you have.
If your doctor finds something that could be breast cancer on a screening test or you have symptoms, they may order a CT scan. CT scans are X-rays that make detailed pictures of parts of the body, such as your breasts and nipple. They might also use a contrast dye to help show changes more clearly. You might be asked to drink lots of water before your scan to help prevent the dye from affecting your kidneys. The scan takes about 30 minutes and you’ll be seated while the images are taken. A healthcare professional called a CT technologist sits in another room and can talk to you through an intercom. They might ask you to hold your breath at certain times during the scan, because movement can blur the images.
The scan can find different kinds of cancer, but it usually helps doctors see if there’s a lump or thickening in the tissue around your nipple and chest wall. It can also find if the cancer has spread to lymph nodes under your arm. It can also show how far the cancer has spread inside your body, including to your lungs, liver or brain.
If you’re diagnosed with invasive breast cancer, the CT scan might be used to help plan your treatment. It can also be used to check if your treatment is working or if the cancer has returned after you’ve finished your treatment. It can also be used to help decide if you need a mastectomy (removal of the whole breast) or other surgery. You might also have a PET scan and a bone scan to find out if the cancer has spread to your bones.
The MRI is a kind of body scan that uses a large magnet linked to a computer. It makes detailed pictures of areas inside the breast. Doctors can use an MRI to look for a lump, or to see whether cancer has spread from one breast to the other.
Doctors can also use an MRI to see whether an area of suspicion on a mammogram or ultrasound has changed over time. This test can help doctors decide if more testing is needed.
During an MRI, your doctor might inject you with a dye to make the tissue and blood vessels show up better. The dye may give you a metallic taste in your mouth. Some people have a reaction to this dye (called gadolinium). The dye can cause allergic reactions and serious problems for some patients with kidney disease.
If your MRI shows a possible problem, you might need more tests to find out if it’s cancer. These tests might include an ultrasound and a biopsy.
Some breast cancers can spread to the lymph nodes. For this reason, doctors might do a sentinel node biopsy to check for lymph nodes that contain cancer cells.
If you have a suspicious lump or change in your breast, talk to your healthcare professional. Inflammatory breast cancer, a rare form of the disease, can cause symptoms that are similar to those of a breast infection, such as pain and swelling. Healthcare professionals often treat breast infections with antibiotics before considering more-serious causes of the symptoms, such as inflammatory breast cancer. If your symptoms don’t go away after a few days of treatment, contact your healthcare professional.
Molecular breast imaging (MBI) uses a short-lived, radioactive tracer to highlight metabolically active cells, including cancer cells. The tracer is absorbed by cells in the breast tissue and shows up on the image, making it easier to detect tumors and other abnormalities. MBI can be used alone or as a supplement to mammography and other breast cancer screening tests.
During the MBI test, you will sit in a chair facing the flat surface of a gamma camera that looks like a mammogram machine. A technician will lower the camera on your breast and apply gentle compression, which should not be painful or uncomfortable. A physician referral is needed for this exam.
The MBI exam takes 28 to 40 minutes, and you can breathe normally during the scan. You will be instructed to remain as still as possible to reduce motion blur. In one study, MBI had a similar incremental cancer detection rate to digital breast tomosynthesis and ultrasound. In addition, MBI has a low false-positive rate, a positive recall rate, and a high negative predictive value.
Unlike mammography, MBI is not affected by dense breast tissue. It can also identify ductal carcinoma in situ (DCIS), which is often missed by mammography and other screening tests. This makes it an excellent choice for supplemental screening in high-risk women. It is also a good option for women who have a lump or other abnormality found on mammography, ultrasound, or MRI. In some cases, your healthcare provider may recommend that you get a biopsy of the area to determine whether it is cancer. If the results are negative, you can continue to receive regular mammograms and other breast health screening.
Breast cancer can often be found with a mammogram, an X-ray of the breast. Doctors recommend women of ages 40 and older have mammograms on a regular basis. The goal is to find cancer before it can be felt or cause symptoms. Many people who have early stage breast cancer don’t have any symptoms. Mammograms can find a lump or other abnormality that may be cancer and help the doctor make a diagnosis.
A mammogram is a series of two X-ray images of each breast, usually taken from the front and the side. A doctor who has special training in mammography reads the X-ray images and looks for early signs of breast cancer. A mammogram can also find cancer that has spread to other parts of the body, such as the lymph nodes in the armpit.
There are different types of mammograms: screening and diagnostic. Screening mammograms are done for people who don’t have any breast symptoms or a family history of breast cancer. This type of mammogram is usually done during the week after a woman’s menstrual period. This is when the breasts are least tender.
A diagnostic mammogram is done when something abnormal is found during a clinical breast exam or on a screening mammogram. It is also used to monitor breast cancer that has already been treated with surgery and/or radiation therapy (these are called surveillance mammograms).
If a lump or other abnormality is seen on the mammogram, doctors can use other tests, such as ultrasound and MRI, to confirm if it’s cancer and if it has spread. If an abnormal mammogram raises a significant suspicion of cancer, doctors may need to remove tissue for biopsy.
Breast cancer treatment includes surgery, chemotherapy, radiation and medicines to reduce the risk that the cancer will come back (hormone therapy and targeted medicine or immunotherapy). You will have regular check-ups.
Invasive lobular carcinoma starts in the breast’s lobules and accounts for 10 to 15 percent of breast cancers. It may spread to the lymph nodes and to other parts of the body.
BCS is surgery to remove the tumor while saving healthy breast tissue. It is the most common surgical treatment for early breast cancer. You can have it as an outpatient or during a hospital stay. Before the surgery, your healthcare provider will explain it to you and answer any questions you have. You will be asked to sign a consent form that gives permission for the procedure. Read the form carefully and ask questions if something is not clear.
During BCS, a lump or abnormality and some of the surrounding normal breast tissue are removed through a small cut (incision). The amount of normal breast tissue that is removed is called the margin. During the operation, your healthcare provider will also check the lymph nodes under your arm to see if cancer cells have spread there. This is done with a sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND).
The surgery can be performed by itself or along with other treatments such as chemotherapy and radiation therapy. Studies have shown that women who choose BCS and receive radiation therapy after surgery have similar long-term survival rates as those who have a mastectomy.
If you are a candidate for BCS, your surgeon will discuss the benefits and risks of this treatment with you. To be a candidate for this treatment, you should have a single breast tumor that is not very large. The tumor should be located close enough to the chest wall that removing it will not change your breast’s appearance too much.
In addition to BCS, you may choose oncoplastic breast-conserving surgery (OBCS). This advanced technique reshapes the breast after the tumor is removed and improves its appearance. The goal is to create a natural-looking breast. Research shows that OBCS offers fewer complications than traditional BCS and results in less scarring and reduced nipple distortion.
Axillary lymph node dissection (ALND) is a surgical procedure that removes the axillary lymph nodes. It is used in breast cancer treatment to prevent local recurrence of the disease and to improve survival. In addition, ALND helps to determine the stage of the disease, which is important for determining what type of systemic therapy to use. However, ALND is also associated with significant morbidity. A number of studies have shown that the procedure can be safely omitted in some patients.
Historically, axillary node dissection was performed after surgical resection of the tumor. However, in the 1990s, the sentinel lymph node biopsy (SLNB) was introduced as a way to determine whether or not the axillary lymph nodes contained cancer cells. SLNB is an important innovation because it allows patients to avoid undergoing complete axillary dissection and its associated morbidity.
The Z0011 study was the first randomized clinical trial to evaluate SLNB in combination with breast-conserving surgery and radiation. The study found that omitting axillary surgery was noninferior to performing full ALND, even when the SLNB indicated that up to two of the axillary lymph nodes were positive.
In a series of 320 women, Chua et al27 reported that palpability of the axillary lymph nodes was not predictive of level III involvement in clinical stage II BC. Pathologic tumour size and LVI were better predictors of level III involvement. Khafagy et al25 reported that 53.2% of patients with four or more positively identified axillary nodes had a level III involved.
Another factor that limits the benefits of omitting axillary dissection is the risk of postoperative swelling (lymphedema). Lymphedema occurs when the fluid in your soft tissues builds up, usually as a result of having several lymph nodes removed. It can be mild to severe and is a serious side effect of many types of surgery, including ALND.
Swelling in the armpits can occur for several weeks after surgery and may be worsened by radiation. You can minimize the risk of developing lymphedema by wearing loose-fitting clothing and massaging your arms regularly. In addition, you can use a compression garment or exercises to manage the swelling.
Chemotherapy uses drugs to kill cancer cells and prevent them from growing or spreading. Depending on the type of chemotherapy, it may also help reduce symptoms. People can get chemotherapy in many ways, including by mouth (pills or liquid), injection or intravenous (IV). In some cases, doctors give chemotherapy directly into the tumor. They may do this through a catheter inserted into a vein, or by using a port surgically installed in the chest or arm. They can also use a pump that’s surgically implanted or external, or by inserting slow-dissolving discs that release medications over time.
Doctors often recommend chemotherapy before surgery to shrink the tumor and reduce the amount of tissue that needs to be removed during a procedure called mastectomy or lumpectomy. Chemotherapy may also be given after a woman has surgery to lower the risk that cancer will come back. This is called adjuvant therapy.
For some breast cancers, doctors can prescribe hormone therapy after chemo to prevent the tumor from regrowing. Specifically, the drugs used in hormone therapy may block or suppress the production of estrogen and progesterone that promote cancer cell growth.
In some cases, doctors can also give a type of chemotherapy called targeted therapy or immunotherapy. These treatments zero in on specific targets (molecules) in or on cancer cells and kill them or stop them from growing. They can be used alone or with other types of treatment, such as radiation therapy or biologic therapy.
A new treatment called molecular profiling tests analyzes cancer cells to find out which kinds of medicines might work best against them. The results can be used to guide treatment decisions and predict how a person might respond to chemotherapy.
If a person gets a good response to chemo, doctors might say the cancer is gone or there’s no evidence of disease on scans, x-rays and blood tests. But that doesn’t always happen. The cancer might still grow or it could recur in the same place or elsewhere in the body.
Talk to your doctor about getting a second opinion from another specialist. This doesn’t usually mean switching doctors. It just means the second doctor sees all of your test results and compares them with what you and your doctor already know.
Radiation uses beams of energy, such as X-rays or protons, to kill cancer cells. It is often used after surgery to reduce the risk that breast cancer will return or to relieve symptoms.
Radiations may be given alone or with other breast cancer treatments. For example, radiation is used with lumpectomy to reduce the chance that cancer will spread from the enlarged tissue back into the rest of the breast. It is also used to treat metastatic breast cancer (cancer that has spread from the breasts to other parts of the body) to shrink tumors and reduce symptoms.
Your doctor will talk to you about the type of radiation treatment that is best for your condition. Radiation can cause side effects such as skin redness and swelling. It can also affect your ability to work and have children. Your doctor will discuss the effects of radiation with you and help you find ways to cope with them.
For external radiation, you lie on a treatment table while the machine delivers radiation from outside your body. You have several treatment sessions, each lasting about a week.
Some doctors use a technique called volumetric modulated arc therapy (VMAT), which uses a rotating treatment machine to shape the beam of radiation to target specific areas of your body. This can improve how the dose is delivered and minimize side effects. MSK is one of a few centers in the world that offer proton therapy, which uses a beam of protons instead of X-rays. Protons are shaped to target tumors in the breast and other parts of the body.
We also use internal radiation, called brachytherapy, to target cancer in the lymph nodes under your arm (called the axillary lymph nodes). For this, we insert radioactive seeds into an applicator that is then placed in your breast. The radiation from the seeds destroys nearby cancer cells and lowers the chance that cancer will return in the armpit.
Sometimes, even after chemotherapy and radiation, your cancer can come back. If this happens, you may need hormone therapy to lower the chances that your cancer will grow again.
