Breast Cancer
Medically reviewed by: Tracey O’Connor, MD
Last Updated: August 2026
What is Breast Cancer?
Breast cancer is a disease where cells in the breast grow out of control. The breast is an organ. It sits on top of the chest muscles and upper ribs. Women, men, and non-binary people can develop breast cancer. A person can develop breast cancer in one or both breasts.
Breast cancer is one of the most common cancers in the U.S. About 1 in 8 women in the U.S. will be diagnosed in their lifetime.
The good news: when found early, breast cancer is often treatable, and many people do well after treatment.
Where Breast Cancer Starts
Breast cancer can start in different areas of the breast, including:
- Lobes – Each breast has 15 to 20 lobes, or sections; these surround your nipple like spokes on a wheel.
- Lobules – Small glands that help make breast milk.
- Nipple(s) – An opening in the skin of the breast where milk comes out. It is surrounded by a darker area of skin called the areola.
- Ducts – Tiny tubes that carry breast milk from the lobules to the nipple.
- Adipose (fatty tissue) – The breast is mostly made up of this.
- Lymph vessels – Tiny “pipes” that help carry blood and fluid away from the breast. These are part of the immune system.
Source: National Cancer Institute
Types of Breast Cancer
There are several different types of breast cancer. These types are based on:
- Where the cancer started
- The type of cells that are changed by the cancer
- The types of genes or proteins the cancer might make
- Ductal Carcinoma in Situ (DCIS)
- Invasive Ductal Carcinoma
- Invasive Lobular Carcinoma
- Inflammatory Breast Cancer
- Metastatic Breast Cancer
Ductal Carcinoma in Situ (DCIS): DCIS is an early form of breast cancer. The cancer cells are in the milk ducts and have not spread outside them. It is called non-invasive, or Stage 0, breast cancer. DCIS is easy to treat and almost always cured.
Invasive Ductal Carcinoma: This is the most common type of breast cancer. It starts in the milk ducts but has spread into nearby breast tissue. It is very treatable when caught early. If not treated, it can spread to other parts of the body.
Invasive Lobular Carcinoma: This cancer starts in the lobules (the parts of the breast that make milk). It has spread into nearby breast tissue. It is very treatable when caught early. If untreated, it can spread to other parts of the body.
Inflammatory Breast Cancer: This type often looks like a rash or infection, rather than a lump. It can cause redness and swelling of the breast. This happens because cancer cells block small drainage channels (lymph vessels) in the skin. Inflammatory breast cancer is often more aggressive and can be harder to treat.
Metastatic Breast Cancer: The cancer has spread to other parts of the body, such as the bones, lungs, liver, or brain. It is also called advanced, or Stage IV, breast cancer.
- Metastatic breast cancer can be found at the first diagnosis (called “de novo”)
- Or, it can come back after earlier breast cancer treatment.
Risk Factors
Risk factors are things that can raise a person’s chance of getting a disease. Just because you have one or more risk factors does not mean you will get cancer. Researchers are learning more about what causes breast cancer. Most people who get breast cancer don’t have clear warning signs, but there are some things that can increase a person’s risk:
- Sex at birth (most cases occur in people born female)
- Being older (risk increases with age)
- Family history of breast cancer or certain inherited gene changes (like BRCA1/BRCA2)
- Personal history of breast cancer or other breast disease
- Never experiencing childbirth or giving birth at an older age
- Race and ethnicity
Having dense breast tissue can also increase a person's risk of breast cancer. Having dense breasts means you have more glandular tissue than fatty tissue. Dense breasts are common and can increase the chance of abnormal growth. If you have dense breasts, your doctor may recommend additional screening options.
Breast Cancer Risk in Black & African American Communities
It’s important to talk about how breast cancer affects Black and African American communities. White people are more likely to get breast cancer. However, Black and African American people diagnosed with breast cancer are more likely to have worse outcomes and lower survival rates.
This includes a higher chance of:
- Getting breast cancer at a younger age
- Getting triple-negative breast cancer (or TNBC, a faster-growing type), about 3 times more often than White people
- Having cancer come back after treatment
- Dying from breast cancer (about 40% more likely than White people)
Experts don’t fully understand why these differences happen. That’s why it’s important to talk with your family about ways to lower risk. Share your family’s health history — who has had cancer, what type, and how old they were. If you’ve had genetic testing, share those results, too, even if they’re normal. This information can help your loved ones make informed choices about their health.
What Does the African American Community Need to Know About Triple Negative Breast Cancer?
Ruby, your virtual community navigator, will help explain what members of the Black and African American community need to know about triple negative breast cancer.
Genetic Testing
Genetic testing looks for changes in your genes that may raise your risk of cancer. If you have cancer, your doctor may suggest seeing a genetic counselor, who will ask about your family’s history of cancer.
One common gene linked to cancer is the BRCA gene. If you test positive, it means you have a change in this gene that can increase your risk of cancers like breast or ovarian cancer. Not everyone with this change will get cancer.
Genetic testing is not the same as biomarker testing. Even if you didn’t inherit a BRCA change (called a germline mutation), your tumor may develop one (called a somatic mutation). This BRCA change appears in your cancer cells, not in the DNA you were born with. A somatic BRCA mutation is not passed down by family members.
Have Questions About Genetics & Cancer?
Our Cancer Support Helpline's Genetics/Genomics Navigator can provide free personalized navigation & resource referrals.
Reducing Your Risk
You cannot prevent all breast cancers, but you can lower your risk by:
- Staying at a healthy weight
- Being physically active
- Limiting alcohol
- Not smoking
- Talking to your doctor about your personal risk
Even if you take steps to lower your risk, you can still get breast cancer. If you get breast cancer, it is not your fault.
Screening and Early Detection
There are many ways to screen for breast cancer. Regular screening is the best way to catch breast cancer early, when it is easiest to treat. Many people with early breast cancer do not notice any symptoms. This is why regular screening is important. Talk with your provider about what screening plan is right for you and when to start.
Some common ways to screen for breast cancer, include:
- Clinical breast exam – A doctor uses their hands to gently check the breasts, underarms, and collarbone area for changes. This exam should be part of a regular visit to your primary care doctor or gynecologist.
- Mammograms – An x-ray of the breast. It can find cancer early, before you can feel it. People at average risk should get a mammogram every year starting at age 40. Due for your mammogram? Here’s what you need to know before you go.
- MRI (magnetic resonance imaging) – Uses radio waves and a powerful magnet to create detailed pictures of the breast. MRI may be used for people at high risk.
- Ultrasound – Uses sound waves to create images of the inside of your breasts. If you have dense breast tissue, your doctor may perform an ultrasound in addition to other tests. This is because a mammogram may not be able to see through the tissue.
- Breast awareness – Knowing how your breasts normally look and feel can help you notice changes. Doing checks monthly can help you find any changes to your breasts’ texture, size, and skin condition. If you have periods, checking your breasts for changes the week after your period can be a good time.
Learn More About Routine Cancer Screenings
Monitoring After Cancer
After a diagnosis and treatment for breast cancer, your doctor will work with you to schedule regular check-ups. Also called surveillance, this is to make sure you stay healthy and the cancer hasn’t come back. It may include many of the screening methods listed above, and these tests may be performed more often than for regular screening.
Surveillance is one part of survivorship, which includes caring for your overall health and well-being after cancer treatment. Coping tips and resources can help you stay informed and manage your care.
Signs & Symptoms
The most common symptom for breast cancer is a lump in the breast or armpit area. Some people have no symptoms, especially early on.
Below are signs of breast cancer to look out for. If you experience any of these symptoms, let your doctor know right away so they can do more tests:
- A new lump in the breast or underarm
- Swelling in part of the breast or armpit area
- Skin changes (redness, dimpling, or flaking)
- Nipple pain or discharge (not breast milk)
- Nipple that becomes flat or points inward (inverted nipple)
- Change in breast size or shape
- Pain in the breast
Diagnosis, Biomarker Testing, and Staging
Diagnosis
Breast cancer is found through routine screening or after symptoms appear. If your doctor suspects breast cancer, they will want to perform additional diagnostic tests, such as:
- Diagnostic Mammogram – Like screening mammograms, diagnostic mammograms are x-rays of the breast. A diagnostic mammogram is often done after a screening mammogram and may take a little longer (30–60 minutes). It may include more angles and “zoomed in” views. This helps to learn more about anything unusual or lumps in the breast.
- Ultrasound – This scan uses sound waves to show whether a lump is solid or filled with fluid. Lumps that are filled with fluid are called cysts. Cysts usually do not lead to cancer. Any solid lumps or masses may lead to cancer.
- MRI – An MRI can show the difference between healthy and unhealthy tissue. Because MRIs do not expose a person to radiation, it may be used to examine a breast lump found during pregnancy.
- Biopsy – A doctor will remove a small amount of breast tissue and look at it under a microscope to check for cancer cells. If cancer cells are found, the doctor will study them to learn as much as possible about the type of cancer. This may include testing the cancer cells for biomarkers.
Biomarker Testing
Biomarkers are characteristics of cancer cells that make them different from normal cells. They can be measured in your blood, tissue, or bodily fluid. In cancer, biomarkers are used to determine your cancer subtype and help choose the best treatment for you. These biomarkers can be proteins, genes, or gene changes (sometimes called mutations).
Here are common breast cancer biomarkers. This list is not complete — your cancer cells may be tested for other biomarkers, too.
- HR status (HR+ or HR-): Cancer cells are tested for hormone receptors (HR). This checks if your cancer uses hormones to grow. HR status is the umbrella category for ER and PR status — all HR+ cancers are ER+ and/or PR+.
- ER and PR status (ER+, PR+): Estrogen (ER) and progesterone receptors (PR) are specific hormone receptors. If present, your doctor may recommend treatments to block these hormones.
- HER2 status: HER2 is a protein called human epidermal growth factor receptor 2. It helps direct cell growth and repair.
- HER2-negative: Cancer cells have normal amounts of HER2.
- HER2-positive: Cancer cells have too much HER2, which can make them grow faster.
- HER2-low: Cancer cells have small amounts of HER2. Some HER2-targeted treatments may be effective.
- Triple-negative: The cancer cells show no estrogen, progesterone, or HER2 receptors.
- BRCA and other gene changes: Even if you didn’t inherit a BRCA change (called a germline mutation), your tumor may develop one (called a somatic mutation). This BRCA change appears in your cancer cells, not in the DNA you were born with. A somatic BRCA mutation is not passed down by family members.
Triple-Negative Breast Cancer (TNBC)
Doctors diagnose TNBC through biomarker testing. Breast cancers that test negative for both hormone receptors and HER2 are considered “triple negative.” Since it is an aggressive form of cancer, it can be more difficult to treat.
This cancer is more common in:
- People who inherit a BRCA gene change (germline mutation)
- People who develop breast cancer before age 40
- Black and African American people
Coping With TNBC?
Learn about 3 key areas where you may need extra support, and resources that can help.
Staging
A cancer’s “stage” is a measure of how advanced it is. The stage of breast cancer depends on three factors:
- Tumor (T) – The size and location of the tumor
- Nodes (N) – Whether cancer cells are found in the lymph nodes and how many nodes are affected
- Metastasis (M) – The spread of cancer to other parts of the body
Example: A small tumor with no involved lymph nodes would be written T1N0. This is the most common presentation.
The cancer is a noninvasive breast cancer, such as ductal carcinoma in situ (DCIS).
The cancer is small and only in the breast tissue, or it might be found in lymph nodes close to the breast.
The cancer is in the breast or nearby lymph nodes or both.
The cancer is a larger tumor with more lymph nodes involved or spread to the chest wall.
The cancer has spread to other parts of the body, such as the bones, liver, or lungs. This stage is also called metastatic breast cancer.
When Breast Cancer Comes Back
Breast cancer that comes back after treatment is called recurrent breast cancer. Breast cancer that comes back may appear in:
- The breast (local)
- Nearby lymph nodes, skin, or chest (regional)
- Other parts of the body (metastatic)
If your breast cancer comes back, your doctor will do many of the same diagnostic tests you first had. This will help them understand where the cancer is located and how best to treat it. This process may be called “restaging.”
Treatment and Side Effects
Treatment for breast cancer depends on the type, stage, your overall health, and personal preferences. Treatments that work for one subtype of cancer may not work for others. You are an important part of the care team to help determine which treatment will be best for you.
Here are some of the most common methods to treat breast cancer:
- Surgery
- Chemotherapy
- Hormone/Endocrine Therapy
- Radiation Therapy
- Targeted Therapy
- Clinical Trials
- Supportive Care
The main types of breast cancer surgery include:
- Sentinel lymph node biopsy: This surgery checks for and removes lymph nodes where fluid from the breast drains first.
- Axillary lymph node dissection (ALND): This surgery removes underarm lymph nodes (usually 10 to 30).
- Lumpectomy: (also called breast-conserving surgery or partial mastectomy): This surgery removes the cancer and a small amount of healthy tissue around it. Only part of the breast is removed. The amount taken out depends on where the tumor is and how big it is.
Mastectomy: This surgery removes the whole breast. In some cases, nearby lymph nodes are also removed. Often, most of the breast skin can be kept, and sometimes the nipple can also be saved (this is called a nipple-sparing mastectomy). Some people choose to have both breasts removed, which is called a double mastectomy.
Surgery can be an important treatment for early-stage breast cancer. This is usually done by a breast surgeon or general surgeon. Side effects may include pain or discomfort, a small risk of infection, and limited movement for a short time while you heal.
Surgery that is done to rebuild the shape and look of the breast after treatment is called breast reconstruction surgery. This is done by a plastic surgeon.
Chemotherapy (also called chemo) uses medications to destroy or damage fast-growing cells like cancer cells. It is used to shrink tumors, slow cancer’s growth, relieve symptoms, or help people live longer. Chemotherapy may be given before surgery (“neoadjuvant” treatment) to shrink a tumor. It can also be given after surgery (“adjuvant” treatment) to kill any remaining cancer cells and reduce the chance of the disease coming back.
Some cancer cells use hormones made by the body to grow. Hormone therapy can help stop or slow the spread of these cells. Hormone therapies work by either stopping the body from making these specific hormones or changing how the body’s hormones act.
Hormones, like estrogen, may fuel breast cancer growth. In this case, doctors use drugs that block estrogen from being created. They also use drugs that stop the hormone from functioning.
Radiation therapy is the use of high-energy rays to kill or damage cancer cells. The goal is to damage as many cancer cells as possible without harming healthy tissue. To lessen damage, doses are very precise, and treatment is usually given in small daily doses over one to several weeks. For breast cancer, most people receive some form of radiation therapy after surgery to the area of the tumor. This is especially true for people who undergo breast conservation surgery. Radiation therapy given after the surgical procedure is called “adjuvant” radiation therapy.
Targeted therapy uses drugs to target specific changes in cancer cells that help them grow, divide, and spread. Biomarker testing helps doctors identify the best targeted therapy options. Targeted therapy drugs are designed to be more precise. They fight cancer cells while causing less harm to healthy cells in the body.
Be sure to ask about clinical trials. These are research studies to test new treatments or learn how to use current treatments better. They find new and better ways to prevent or treat cancer. Some trials also test ways to make the experience of going through treatment less difficult or improve side effects.
Trials are offered for many cancers, at all different stages. Everyone is not eligible for every trial. If you have cancer that has come back or spread, it is especially important to ask about clinical trials.
Maintaining your best possible quality of life is an important goal. Some care you receive may not treat your cancer. Instead, it will address possible symptoms caused by your cancer or side effects from treatment, such as hot flashes, pain, or lymphedema (swelling). It may help you with social, emotional, or spiritual concerns. This kind of care is called palliative care or supportive care.
Many hospitals offer palliative care at any time during the cancer experience. Palliative care is not hospice. It is often provided by a palliative care specialist. This person is a doctor or nurse who focuses on symptoms, side effects, and emotional needs of patients. If you are not referred to a palliative care specialist soon after you learn you have breast cancer, ask to see one.
Side Effects
It helps to learn about the side effects of treatment before you begin, so you will know what to expect. When you know more, you can work with your care team to manage your quality of life during and after treatment.
Note: Before making decisions about your care, you have the right to a second — and even third — opinion at any point in your cancer experience. This can help you confirm your diagnosis, understand treatment options, learn about clinical trials, and help you choose the right care team. Read more about getting a second opinion.
I needed someone who fit with me and my goals — to live fully, with a good quality of life, while not ignoring the needs of my family.
Coping With Breast Cancer
An important step in managing your cancer and its treatment is to be informed. Breast cancer may affect different areas of your life. If you are experiencing any challenges in these areas, there are resources to help:
- Navigating mental health
- Body image and feeling of loss
- Urinary, intimacy, sex, and fertility changes
- Managing the cost of cancer treatment
- Support for caregivers
- Long-term survivorship
A cancer diagnosis can bring many feelings — fear, anger, sadness, or worry. These are normal. Support can help you feel more in control. Consider:
- Support groups (in person or online)
- Counseling with an oncology social worker
- Individual, couples, or family therapy with an onco-psychologist
- Peer mentors (one‑on‑one connections with someone who has been through breast cancer)
- For anyone navigating breast cancer or supporting someone with this diagnosis, join the MyLifeLine breast cancer forum.
- Stress‑reduction (mindfulness, gentle exercise, breathing techniques, doing activities you enjoy)
It’s normal to worry about changes in how you look. Surgery and treatment can affect your body. You may feel sad about losing your breast or changes like less feeling in the breast or not being able to breastfeed.
To cope:
- Give yourself time to adapt to your new body, both emotionally and physically. It is possible to adapt and improve over time. It’s also okay to feel sad, angry, or frustrated.
- Ask your care team about ways to improve any physical limitations that linger after treatment.
- Consider options like physical therapy, tattooing, or skin treatments that can help with body image concerns.
- Try to focus on your strength and what you’ve been through.
- Connect with other survivors for support and advice.
Sometimes, side effects from cancer treatments can lead to urinary, sexual, intimacy, and fertility issues. Changes like vaginal dryness, discomfort, and bladder symptoms are very common. Treatment can also affect your ability to get pregnant in the future.
Talk to your care team early and often about these concerns. There are steps you can take before, during, and after treatment to help manage these changes.
Worries about costs of care are common when you are facing a cancer diagnosis. Learn how to talk about the financial side of cancer and where to go for help.
The ripples of a cancer diagnosis extend to spouses, partners, siblings, children, and friends. Many of these family members will find they now need to take on the role of caregiver — something they may never have done before.
The period after treatment may involve physical, emotional, and lifestyle adjustments. You may be adapting to a “new normal.” You may have long-term treatment effects, worries about recurrence, or questions about care.
Talking to your cancer care team and your primary care provider can help you manage this transition. Get support for physical activity, nutrition, a healthy emotional life, and management of any health concerns that may arise.
Tips for Talking With Your Care Team
Bring these questions to your appointments:
- What type and stage of breast cancer do I have? Ask your doctor to explain the size, lymph nodes, and whether it has spread.
- Has my cancer been tested for biomarkers? Ask about the results and what they mean for your treatment options.
- What are my treatment options? Ask about the pros and cons of each option.
- If you recommend surgery, what are my options for keeping my breasts or breast reconstruction? Ask about different surgery options, like keeping breasts or nipples, implants, reconstruction using your own body’s tissue — and what to expect with each.
- What side effects should I expect, and how can I manage them? Ask about pain, hair loss, hormone changes, urinary and sexual changes, and fertility concerns. Also ask about options to plan ahead for and manage these side effects.
- How long will treatment last, and how often are visits? Ask about the schedule and timing.
- Can I join a clinical trial?
- What support services are available for me and my caregivers? Consider support for nutrition, social work, mental health, sexual health, fertility, and financial counseling.
Getting the Support You Want and Need
Breast cancer brings up many feelings. It affects you, your family, and your loved ones. It is normal to feel sad, anxious, worried, shocked, stressed, or panicked. Remember that cancer can impact anyone, and every person deserves good care and support.
Consider these three tips:
- Be gentle with yourself when you are feeling stressed. You may feel more anxious when it gets close to a doctor’s appointment. It may help to take someone with you for support and to be an extra set of eyes or ears during the visit.
- Share your feelings with trusted friends, family members, a case manager or counselor, or a clergyperson or spiritual advisor.
- Focus on what you can control. Take things one small step at a time, from diagnosis, through treatment, to survivorship.
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