Breast Cancer in Women: What You Need to Know

Breast cancer is not a single disease — it encompasses many different types, each with distinct characteristics, growth patterns, and treatment approaches. Understanding the specific type is essential for determining the most effective treatment plan.

Breast cancers are first classified as either noninvasive or invasive. Noninvasive cancers, also called carcinomas in situ, have not spread beyond the ducts or lobules where they started. The most common noninvasive form is ductal carcinoma in situ (DCIS), which is confined to the milk ducts and is highly treatable. Lobular carcinoma in situ (LCIS) is not a true cancer but a marker of increased risk for developing invasive breast cancer later.

Invasive cancers have spread beyond the original tissue into the surrounding breast tissue. The most common type, accounting for approximately 80 percent of invasive cases, is invasive ductal carcinoma (IDC). It begins in the milk ducts and breaks through the duct wall into the surrounding fatty tissue. Invasive lobular carcinoma (ILC) accounts for about 10 percent of invasive cases and starts in the milk-producing lobules.

Several other types are less common but important to recognize. Inflammatory breast cancer is a rare, aggressive form that causes redness, swelling, and warmth in the breast without a distinct lump. Paget’s disease of the nipple affects the skin of the nipple and areola, causing crusting, redness, and flaking. Triple-negative breast cancer lacks receptors for estrogen, progesterone, and HER2 and tends to be more aggressive. Angiosarcoma, phyllodes tumors, medullary, mucinous, tubular, and papillary carcinomas are rarer subtypes.

Breast cancers are also classified by their receptor status, which is critical for treatment decisions. Hormone receptor-positive cancers (ER+ or PR+) grow in response to estrogen or progesterone and account for about 70 percent of all breast cancers. HER2-positive cancers have excess HER2 protein that promotes cancer growth. Triple-negative cancers lack all three receptors.

Genomic profiling further categorizes breast cancer into molecular subtypes — Luminal A, Luminal B, HER2-enriched, and Basal-like (typically triple-negative) — each with different prognoses and treatment responses.

The symptoms of breast cancer can vary widely, and many early-stage breast cancers cause no symptoms at all. This is why regular mammography screening is so important — it can detect cancer long before any noticeable changes occur.

The most common symptom of breast cancer is a new lump or mass in the breast or underarm area. These lumps are often painless, hard, and have irregular edges, though they can sometimes be tender, soft, or rounded. Any new lump should be evaluated by a healthcare professional.

Other symptoms can include:

• Swelling of all or part of the breast, even if no lump is felt
• Skin dimpling or puckering that resembles the texture of an orange peel
• Nipple discharge that is clear, bloody, or yellowish
• Nipple retraction or inversion
• Redness, scaling, or thickening of the nipple or breast skin
• Changes in the size or shape of the breast
• Warmth or swelling in the breast
• Swollen lymph nodes under the arm or around the collarbone
• Persistent breast pain that does not go away

It is important to remember that most breast symptoms are not caused by cancer. Benign conditions such as cysts, fibroadenomas, infections, and hormonal changes can produce similar symptoms. However, any persistent change should be evaluated by a doctor.

Many breast cancers detected through screening mammograms are found at an early stage when they are too small to be felt and have not yet caused symptoms. This is why following recommended screening guidelines is one of the most important things you can do for your breast health.

Breast cancer is caused by genetic mutations that allow cells in the breast to grow and divide uncontrollably. These mutations can be inherited or acquired over time. While the exact cause is not always known, researchers have identified many factors that increase the risk of developing breast cancer.

Genetic mutations play a significant role. The most well-known are BRCA1 and BRCA2 gene mutations. Women with a BRCA1 mutation have a 55 to 72 percent chance of developing breast cancer by age 80, while those with a BRCA2 mutation have a 45 to 69 percent chance. Other genes associated with increased breast cancer risk include PALB2, PTEN, TP53, CHEK2, ATM, CDH1, and STK11.

Family history is important. Having a first-degree female relative (mother, sister, or daughter) with breast cancer approximately doubles your risk. Having two or more first-degree relatives triples the risk. The risk is higher if the relative was diagnosed before menopause or had cancer in both breasts.

Age is one of the strongest risk factors. The risk of breast cancer increases with age, and most cases are diagnosed in women over 55. About 2 in 3 women with invasive breast cancer are 55 or older at the time of diagnosis.

Reproductive and hormonal factors influence risk. Starting menstruation before age 12, going through menopause after age 55, having a first child after age 30, not breastfeeding, and never having a full-term pregnancy are all associated with a slightly higher risk. Taking combined estrogen-progesterone hormone replacement therapy for more than five years during menopause also increases risk.

Lifestyle factors that raise risk include drinking alcohol regularly (especially more than one drink per day), being overweight or obese after menopause, and not getting enough physical activity.

Other risk factors include having dense breast tissue (which can make mammograms harder to read), a personal history of breast cancer or certain benign breast conditions, radiation therapy to the chest before age 40, and exposure to the drug diethylstilbestrol (DES), which was used to prevent miscarriage between 1940 and 1971.

Race and ethnicity also play a role. White women in the United States have the highest overall incidence of breast cancer, but Black women are 40 percent more likely to die from the disease. This disparity is due to a combination of factors, including higher rates of aggressive subtypes, younger age at diagnosis, and differences in healthcare access and quality.

It is important to remember that most women with known risk factors never develop breast cancer, and approximately 3 out of 4 women who are diagnosed have no identifiable risk factors beyond age.

The diagnosis of breast cancer involves a series of steps, beginning with detection and ending with a detailed analysis of the cancer to guide treatment.

Mammography is the primary screening tool for breast cancer. A mammogram is a low-dose X-ray of the breast that can detect tumors years before they can be felt. Screening mammograms are recommended starting at age 40 to 45, depending on the guidelines you follow. Diagnostic mammography is used when a symptom or abnormal screening finding needs further evaluation.

If an abnormality is found, the next step is typically an ultrasound. Ultrasound uses sound waves to create images of the breast tissue and can help distinguish a solid mass (which may be cancerous) from a fluid-filled cyst (which is usually benign).

Breast MRI may be used for women at high risk, to evaluate the extent of known cancer, or to examine areas that are hard to assess with mammography and ultrasound. MRI uses magnetic fields and a contrast dye to create detailed images.

The only definitive way to diagnose breast cancer is through a biopsy. During a biopsy, a sample of tissue is removed from the suspicious area and examined under a microscope. The most common method is a core needle biopsy, which uses a hollow needle to remove tissue. Fine needle aspiration uses a thinner needle and is more often used for fluid-filled cysts. Surgical biopsies, where an incision is made to remove tissue, are less common now but may be needed in certain situations.

The biopsy sample is tested for several key features:

• Hormone receptors (estrogen receptor ER and progesterone receptor PR): Determines whether the cancer is hormone receptor-positive
• HER2 status: Tests for excess HER2 protein, which guides targeted therapy
• Grade: How much the cancer cells differ from normal cells, indicating how quickly they may grow
• Genomic profiling: Tests such as Oncotype DX, MammaPrint, and PAM50 analyze the genes in the cancer cells to predict the risk of recurrence and help guide treatment decisions

Staging tests determine how far the cancer has spread. These may include CT scans, bone scans, PET scans, and blood tests. Breast cancer is staged from 0 to IV, with stage 0 being noninvasive and stage IV meaning the cancer has spread to distant organs.

While breast cancer cannot always be prevented, there are several measures you can take to reduce your risk. For women at average risk, lifestyle choices and regular screening are the most important preventive strategies.

Maintain a healthy weight. Being overweight or obese after menopause increases breast cancer risk, partly because fat tissue produces estrogen, which can fuel hormone receptor-positive cancers. Aim for a body mass index in the healthy range.

Stay physically active. Regular exercise helps regulate hormone levels, supports a healthy immune system, and helps maintain a healthy weight. Aim for at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous activity each week.

Limit alcohol. Alcohol is classified as a known carcinogen. Even one drink per day increases breast cancer risk, and the risk rises with the amount consumed. For women, the recommendation is no more than one drink per day, and ideally less.

Breastfeed if possible. Breastfeeding, especially for a year or longer, has been shown to reduce the risk of breast cancer. The protection may be due to hormonal changes that suppress ovulation and reduce lifetime exposure to estrogen.

Limit postmenopausal hormone therapy. If you take hormone replacement therapy to manage menopause symptoms, use the lowest effective dose for the shortest possible time. Combination therapy with estrogen and progesterone for more than five years increases breast cancer risk.

Get regular mammograms. Screening mammography can detect breast cancer at an early, more treatable stage. The American Cancer Society recommends annual mammograms from age 45 to 54, with the option to start at 40 and to continue every one to two years after 55. The U.S. Preventive Services Task Force recommends mammograms every two years starting at 40.

For women at high risk due to family history, genetic mutations, or other factors, additional measures may be recommended:

• Genetic counseling and testing for BRCA and other mutations
• Earlier and more frequent screening, including breast MRI
• Chemoprevention with medications such as tamoxifen, raloxifene, or aromatase inhibitors
• Risk-reducing mastectomy (removal of breasts) or oophorectomy (removal of ovaries) in carefully selected high-risk cases

Regular breast self-awareness is also important. Know how your breasts normally look and feel, and report any changes to your doctor promptly.

The outlook for breast cancer has improved dramatically over the past several decades, thanks to advances in screening, surgical techniques, chemotherapy, hormone therapy, targeted therapy, and immunotherapy.

Five-year relative survival rates for breast cancer in women:

• Localized (confined to the breast): 99 percent
• Regional (spread to nearby lymph nodes): 86 percent
• Distant (metastasized to distant organs): 31 percent
• All stages combined: 91 percent

These figures mean that overall, about 91 percent of women diagnosed with breast cancer are alive five years after their diagnosis. When the cancer is caught early while still confined to the breast, the survival rate is 99 percent.

Several factors influence an individual’s prognosis. The stage at diagnosis is the most important factor. Early-stage cancers have an excellent prognosis, while advanced-stage cancers are more challenging to treat. Receptor status matters — hormone receptor-positive cancers tend to grow more slowly and respond well to hormone therapy. HER2-positive cancers can be aggressive but respond well to targeted therapies. Triple-negative breast cancer is more aggressive and has fewer treatment options, though immunotherapy has improved outcomes for some subtypes. Tumor grade, genomic profile, age, overall health, and response to treatment all affect the outlook.

Breast cancer can recur, even years after successful treatment. The risk of recurrence is highest within the first five years but does not disappear entirely. Regular follow-up care, including physical exams, mammograms, and sometimes additional imaging, is essential for detecting recurrence early.

Significant disparities exist in breast cancer outcomes. Black women in the United States have a 40 percent higher mortality rate from breast cancer than White women, despite having slightly lower incidence rates. This disparity is driven by a combination of factors, including higher rates of aggressive subtypes such as triple-negative breast cancer, younger age at diagnosis, delayed detection, and unequal access to high-quality care.

With continued progress in early detection and treatment, the outlook for women diagnosed with breast cancer continues to improve, and more women than ever are surviving the disease and living full, healthy lives after treatment.

Treatment for breast cancer is highly individualized and depends on the type, stage, receptor status, genomic profile, age, and overall health of the patient. A multidisciplinary team — including a surgeon, medical oncologist, radiation oncologist, pathologist, and genetic counselor — works together to develop a comprehensive treatment plan.

Surgery is often the first step in treatment. Breast-conserving surgery (lumpectomy) removes only the tumor and a small margin of surrounding tissue, preserving most of the breast. It is typically followed by radiation therapy. Mastectomy removes the entire breast. There are several types, including simple or total mastectomy, modified radical mastectomy (removal of breast and underarm lymph nodes), nipple-sparing mastectomy, and contralateral prophylactic mastectomy (removal of the healthy breast in high-risk women). Sentinel lymph node biopsy determines whether the cancer has spread to the lymph nodes. If it has, an axillary lymph node dissection may be performed to remove additional nodes. Breast reconstruction surgery can be performed at the same time as mastectomy or at a later date.

Radiation therapy uses high-energy beams to destroy cancer cells. External beam radiation is the most common type and is usually given daily for three to six weeks after lumpectomy or after mastectomy if there is a high risk of recurrence. Hypofractionated radiation delivers larger daily doses over a shorter period. Brachytherapy (internal radiation) places radioactive sources inside the breast for a shorter treatment course. Intraoperative radiation therapy delivers a single dose during surgery.

Chemotherapy uses drugs to kill cancer cells throughout the body. It may be given after surgery (adjuvant chemotherapy) to eliminate any remaining cancer cells and reduce the risk of recurrence, or before surgery (neoadjuvant chemotherapy) to shrink a large tumor and make it more operable. Chemotherapy is recommended when there is a higher risk of recurrence based on tumor size, lymph node involvement, grade, and other factors.

Hormone therapy is a cornerstone of treatment for hormone receptor-positive breast cancers, which account for about 70 percent of all cases. Tamoxifen blocks estrogen from attaching to cancer cells and is the standard for premenopausal women. Aromatase inhibitors — including anastrozole, letrozole, and exemestane — lower estrogen levels in the body and are typically used in postmenopausal women. SERDs (selective estrogen receptor degraders) such as fulvestrant and elacestrant are options for advanced disease. LHRH agonists suppress ovarian estrogen production in premenopausal women. Hormone therapy is usually taken daily for five to ten years.

Targeted therapy attacks specific molecules involved in cancer growth. For HER2-positive breast cancer, drugs such as trastuzumab (Herceptin), pertuzumab (Perjeta), and antibody-drug conjugates like trastuzumab emtansine (Kadcyla) and trastuzumab deruxtecan (Enhertu) are highly effective. CDK4/6 inhibitors — palbociclib, ribociclib, and abemaciclib — are used in combination with hormone therapy for advanced ER-positive, HER2-negative breast cancer. PARP inhibitors such as olaparib and talazoparib are effective for BRCA-mutated breast cancers. PI3K inhibitors and mTOR inhibitors are options for specific genetic alterations.

Immunotherapy helps the immune system recognize and attack cancer cells. Pembrolizumab (Keytruda) is approved for triple-negative breast cancer that expresses PD-L1 and for early-stage triple-negative breast cancer when combined with chemotherapy.

Treatment is often given in phases. Primary treatment addresses the cancer in the breast and nearby lymph nodes. Adjuvant therapy (systemic treatment after surgery) reduces the risk of recurrence. For advanced or metastatic breast cancer, treatment focuses on controlling the disease, managing symptoms, and maintaining quality of life. Clinical trials may offer access to promising new treatments for all stages of breast cancer.

Diet plays an important role in both reducing the risk of breast cancer and supporting recovery during and after treatment. While no single food or diet can guarantee prevention, a well-balanced eating pattern can make a meaningful difference.

A diet rich in fruits and vegetables provides antioxidants and phytochemicals that may help protect cells from DNA damage. Cruciferous vegetables such as broccoli, cauliflower, cabbage, kale, and Brussels sprouts contain compounds that have been linked to lower breast cancer risk. Berries, tomatoes, leafy greens, and citrus fruits are also excellent sources of protective nutrients.

Whole grains and legumes provide fiber, which may help reduce breast cancer risk by lowering estrogen levels in the blood. Good sources include oats, quinoa, brown rice, whole wheat, beans, lentils, and chickpeas.

Healthy fats are important for overall health. Olive oil, avocados, nuts, seeds, and fatty fish such as salmon, mackerel, and sardines provide omega-3 fatty acids with anti-inflammatory properties. The Mediterranean diet, which emphasizes these foods, has been associated with a lower risk of breast cancer.

Foods to limit include red and processed meats, which have been linked to an increased cancer risk. Sugar-sweetened beverages and highly processed foods contribute to weight gain, which raises risk. Limiting alcohol is one of the most important dietary measures — even moderate drinking increases breast cancer risk, so keeping intake to no more than one drink per day is recommended.

Soy is safe for women with breast cancer and may even be protective. Studies have shown that moderate consumption of whole soy foods such as tofu, edamame, and tempeh does not increase risk and may improve outcomes. Soy supplements, on the other hand, are not recommended.

During treatment, nutritional needs may change. Chemotherapy and radiation can cause nausea, taste changes, loss of appetite, and fatigue. Eating small, frequent meals; choosing nutrient-dense foods; staying hydrated; and prioritizing protein for healing and immune support are important strategies. A registered dietitian who specializes in oncology nutrition can provide personalized guidance.

Vitamin D and calcium are especially important for women on aromatase inhibitors or hormone therapy, which can accelerate bone loss. Good sources of calcium include dairy products, fortified plant milks, leafy greens, and almonds. Vitamin D can be obtained from sunlight exposure, fortified foods, and supplements if levels are low.

Maintaining a healthy weight through diet is one of the most important goals. Obesity after menopause increases estrogen levels and raises the risk of breast cancer recurrence. For women who have completed treatment, a healthy diet and regular exercise can improve long-term outcomes and reduce the risk of other chronic diseases.

Breast cancer is the most common cancer among women worldwide, affecting approximately 1 in 8 women over the course of their lifetime. It occurs when cells in the breast grow uncontrollably, most often beginning in the milk ducts (ductal carcinoma) or the milk-producing lobules (lobular carcinoma). The majority of breast cancers are invasive and can spread to nearby lymph nodes and distant organs if not treated. The most important risk factors include being female, advancing age, genetic mutations such as BRCA1 and BRCA2, a strong family history of breast or ovarian cancer, and lifestyle factors such as alcohol consumption, obesity, and physical inactivity. Hormonal and reproductive factors also influence risk, including early menstruation, late menopause, hormone therapy use, and not breastfeeding. Screening mammography is the most effective tool for detecting breast cancer early, when it is most treatable. Diagnosis is confirmed through biopsy, and the cancer is analyzed for hormone receptors, HER2 status, and genomic markers that guide treatment. Treatment is highly individualized and may include surgery, radiation, chemotherapy, hormone therapy, targeted therapy, and immunotherapy. Survival rates have improved dramatically, with a five-year relative survival rate of 99 percent for localized disease and 91 percent overall. Prevention centers on maintaining a healthy weight, staying physically active, limiting alcohol, breastfeeding, getting regular mammograms, and for high-risk women, considering genetic testing and preventive medications or surgery. With advances in early detection, personalized treatment, and supportive care, the outlook for women diagnosed with breast cancer continues to improve.