# Breast Cancer **Table of Contents** **Table of Contents** [Overview](#section-overview "Overview") [Signs & Symptoms](#section-431 "Signs & Symptoms") [Causes](#section-436 "Causes") [Risk Factors](#section-441 "Risk Factors") [Preventing Breast Cancer](#section-446 "Preventing Breast Cancer") [Average risk prevention](#section-486 "Average risk prevention") [High risk prevention](#section-501 "High risk prevention") [Diagnosing and Staging Breast Cancer](#section-506 "Diagnosing and Staging Breast Cancer") [Treatments & Services](#section-521 "Treatments & Services") ## Overview Breast cancer develops when abnormal cells grow uncontrollably in breast tissue. It often begins in the ducts that carry milk to the nipple or in the lobules that produce milk, but it can arise in other areas of the breast as well. While breast cancer can occur in both women and men, it is far more common in women and is one of the most frequently diagnosed cancers in the United States. Thanks to increased awareness, screening, and advances in treatment, survival rates continue to improve. Earlier detection through mammograms and a more personalized approach to care have led to better outcomes and a deeper understanding of the disease. Having breast cancer can feel overwhelming, but effective treatment options are available. Many people benefit from a combination of therapies tailored to their specific type and stage of breast cancer, as well as their overall health and preferences. ## Signs & Symptoms Breast cancer symptoms can vary, and some people may not notice any changes early on. When symptoms do occur, they may include: - A lump or area of thickened tissue in the breast that feels different from surrounding tissue - Changes in breast size, shape, or appearance - Dimpling or puckering of the breast skin - A nipple that becomes newly inverted - Peeling, scaling, or flaking of the skin around the nipple or on the breast - Redness or pitting of the breast skin, resembling an orange peel These symptoms can also be caused by conditions other than cancer, but it is important to have any new or persistent changes checked by your doctor. Early evaluation can help identify issues sooner, when they may be easier to treat. ## Causes The exact cause of breast cancer is not fully understood. Breast cancer develops when some breast cells acquire changes in their DNA that allow them to grow and divide more rapidly than normal cells. Over time, these abnormal cells can form a lump or mass and may spread to nearby lymph nodes or other parts of the body. Breast cancer most often begins in the milk ducts (invasive ductal carcinoma). It can also start in the glandular tissue that produces milk (invasive lobular carcinoma) or, less commonly, in other breast tissues. Researchers have identified hormonal, lifestyle and environmental factors that may increase risk, but it is not clear why some people with no known risk factors develop breast cancer and others with risk factors do not. It is likely the result of a complex interaction between genetics and environmental influences. **Inherited Breast Cancer** Only about 5 to 10 percent of breast cancers are linked to inherited gene mutations. The most well-known are BRCA1 and BRCA2, which significantly increase the risk of both breast and ovarian cancers. If you have a strong family history of breast or related cancers, your doctor may recommend genetic counseling or testing to help assess your risk. A genetic counselor can discuss testing options and help you make informed decisions based on your personal and family history. ## Risk Factors A risk factor is anything that increases the likelihood of developing breast cancer, but having one or even several risk factors does not mean you will develop the disease. Many people diagnosed with breast cancer have no obvious risk factors other than being female. Factors that may increase risk include: - **Being female:** Breast cancer is far more common in women than in men. - **Increasing age:** Risk rises as you get older. - **Personal history of breast conditions:** Previous biopsies showing atypical hyperplasia or lobular carcinoma in situ (LCIS) increase risk. - **Personal history of breast cancer:** Having breast cancer in one breast raises the risk of developing cancer in the other breast. - **Family history:** Having a close relative diagnosed with breast cancer, especially at a younger age, may increase risk. - **Inherited gene changes:** Mutations such as BRCA1 and BRCA2 can greatly increase risk, although they do not make cancer inevitable. - **Radiation exposure:** Receiving radiation therapy to the chest in childhood or early adulthood increases risk. - **Obesity:** Being overweight or obese after menopause is associated with a higher risk. - **Reproductive history:** Starting periods before age 12 or beginning menopause later in life increases lifetime exposure to hormones that influence risk. - **Pregnancy history:** Having a first pregnancy after age 30 or never having been pregnant may increase risk. - **Postmenopausal hormone therapy:** Using combined estrogen and progesterone hormone therapy increases risk, which decreases after stopping treatment. - **Alcohol use:** Drinking alcohol is linked to a higher risk of breast cancer. ## Preventing Breast Cancer Many factors that influence breast cancer risk cannot be changed, such as age or family history. However, certain lifestyle choices and medical strategies may help reduce risk. Talk with your doctor about what prevention options are right for you. ## Average risk prevention Breast cancer risk reduction for women with an average risk ##### Screening and early detection Discuss when to begin screening exams such as mammograms and clinical breast exams. Work with your doctor to create a screening plan that fits your health needs. ##### Breast awareness Becoming familiar with how your breasts normally look and feel can help you notice changes. Report any new lumps, skin changes, or other concerns to your doctor. ##### Limit alcohol If you drink alcohol, limit intake to no more than one drink per day. ##### Regular physical activity Aim for at least 30 minutes of exercise on most days. Start slowly if you are not currently active. ##### Limit postmenopausal hormone therapy Combination hormone therapy may increase risk. Use the lowest dose for the shortest time needed, and discuss risks and benefits with your doctor. ##### Maintain a healthy weight Achieving and maintaining a healthy weight through balanced eating and regular activity may help lower risk. ##### Choose a healthy diet A Mediterranean-style diet that emphasizes fruits, vegetables, whole grains, legumes, nuts, and healthy fats like olive oil may offer some benefit. ## High risk prevention Breast cancer risk reduction for women with a high risk ##### Preventive medications (chemoprevention) Estrogen-blocking medications such as selective estrogen receptor modulators or aromatase inhibitors may reduce risk in women with a significantly elevated risk. These medications can have side effects, so they are reserved for specific cases. ##### Preventive surgery Women with a very high risk may consider preventive removal of the breasts (prophylactic mastectomy) or ovaries (prophylactic oophorectomy) to reduce the risk of breast and ovarian cancer. Decisions about surgery are highly personal and require careful discussion with a specialist. ## Diagnosing and Staging Breast Cancer To diagnose breast cancer, your doctor may use several tests to confirm the presence of cancer, determine its type, and guide treatment. Depending on your situation, additional tests may be recommended to gather more information. - **Breast Exam:** Your doctor will check both breasts and nearby lymph nodes for lumps or other abnormalities. - **Mammogram:** This X-ray of the breast is a common screening tool. If something unusual shows up, a diagnostic mammogram may be used to get a closer look. - **Breast Ultrasound:** Ultrasound uses sound waves to distinguish between solid masses and fluid-filled cysts. - **Biopsy:** This is the only way to confirm a breast cancer diagnosis. A small sample of tissue is removed (usually with a needle guided by imaging) and sent to a lab. The biopsy reveals whether the cells are cancerous, what type they are, how aggressive the cancer is (its grade), and whether it has hormone or other receptors that may affect treatment. - **Breast MRI:** MRI uses magnets and radio waves, not radiation, to create detailed images. A contrast dye is injected beforehand to enhance image clarity. After diagnosis, your doctor will determine the stage of your breast cancer and how far it has grown or spread. Staging, from 0 to 4, guides treatment and is based on tumor size, lymph node involvement, and whether the cancer has spread. Stage of DiseaseWhat It MeansStage 0 (In Situ)Non-invasive cancer (often DCIS), abnormal cells are found only in the ducts or lobules and haven't spread, and typically highly treatable and caught through routine screeningStage 1 (Early Stage Invasive)Tumor is under 2 cm and may or may not have reached nearby lymph nodes, cancer has started to invade surrounding tissue but is still localized, and high chance of successful treatmentStage 2 (Localized Invasive)Tumor is 2–5 cm and may have spread to a few nearby lymph nodes, still considered treatable, but may require a combination of therapiesStage 3 (Locally Advanced)Tumor is larger than 5 cm or has spread to multiple lymph nodes or surrounding breast/chest wall tissue, more aggressive treatment often needed, including chemo, surgery, and/or radiationStage 4 (Metastatic)Cancer has spread beyond the breast and lymph nodes to other organs (bones, lungs, liver, brain, etc.), treatment focuses on managing the disease and improving quality of life ## Treatments & Services Treatment Options Breast cancer treatment depends on the type and stage of cancer, as well as your overall health and personal preferences. Many people receive a combination of therapies. Your care team will work with you to create a personalized treatment plan. Common treatment options include: [Chemotherapy](/all-treatments-services/chemotherapy) [Immunotherapy](/all-treatments-services/immunotherapy) Services Options [Medical Oncology](/all-treatments-services/medical-oncology)