One in eight women in the United States will be diagnosed with breast cancer in her lifetime, making it the most commonly diagnosed cancer among American women after skin cancer. For 2026, the American Cancer Society estimates about 321,910 new cases of invasive breast cancer in women, roughly 60,730 new cases of ductal carcinoma in situ (DCIS), and about 42,140 deaths. Behind these statistics is both a sobering reality and genuine cause for hope – based on 2016-2022 SEER data, the 5-year relative survival rate is about 92 percent overall, and close to 100 percent when the cancer is caught at a localized stage. Understanding your personal risk, following screening guidelines, and knowing what treatment advances are available can make a critical difference. For an overview of major health conditions, see our medical conditions guide.
Medical disclaimer: This article is for general education only and is not a substitute for professional medical advice, diagnosis, or treatment. Screening and treatment decisions – including which drugs are appropriate and at what dose – should be made with your own clinicians. If you notice a new breast change, contact your doctor promptly rather than relying on general information.
See a doctor promptly – do not wait for your next scheduled mammogram – if you notice:
- A new lump or mass in the breast or underarm, or an area that feels distinctly different from the surrounding tissue
- Skin dimpling, puckering, or thickening; a pulled-in (inverted) nipple; or scaly, red, or flaky skin of the nipple or breast
- Nipple discharge other than breast milk, especially if bloody, or a new change in breast size or shape
- Inflammatory breast cancer warning signs: rapid redness, swelling, warmth, and an orange-peel skin texture (peau d’orange) developing over days to weeks, often without a distinct lump. This aggressive type can be mistaken for a breast infection – seek urgent evaluation.
These signs do not always mean cancer, but they need timely professional evaluation. Men who notice a lump or change beneath the nipple should be evaluated too.
Types of Breast Cancer
Breast cancer is not a single disease but a group of diseases classified by where they originate, whether they have spread beyond their site of origin, and their molecular characteristics. The two broadest categories are non-invasive (in situ) and invasive breast cancer.
Non-Invasive Breast Cancer
Ductal carcinoma in situ (DCIS) is the most common non-invasive type. Abnormal cells are confined to the milk ducts and have not penetrated into surrounding breast tissue. DCIS accounts for a significant share of breast cancers detected through screening. It is considered stage 0 and has an excellent prognosis, though it is treated to reduce the risk of progression to invasive cancer. Lobular carcinoma in situ (LCIS) is not considered a true cancer but rather a marker of increased breast cancer risk that may warrant enhanced surveillance.
Invasive Breast Cancer
Invasive ductal carcinoma (IDC) is the most common type, accounting for 70 to 80 percent of all invasive breast cancers. It starts in the milk ducts and invades surrounding breast tissue. Invasive lobular carcinoma (ILC) accounts for approximately 10 to 15 percent and begins in the lobules (milk-producing glands). ILC tends to be harder to detect on mammography because it often does not form a distinct mass. Less common types include inflammatory breast cancer (aggressive, causing redness and swelling), Paget disease of the nipple, and phyllodes tumors.
Molecular Subtypes
Modern breast cancer treatment is guided by molecular profiling, which classifies tumors based on receptor status. According to the National Cancer Institute, the key markers are estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Hormone receptor-positive (HR+) cancers account for roughly 70 percent of cases and are driven by hormones. HER2-positive cancers (about 15 to 20 percent) overproduce the HER2 protein, making them susceptible to HER2-targeted drugs. Triple-negative breast cancer (TNBC) – lacking ER, PR, and HER2 – accounts for 10 to 15 percent and historically had fewer targeted options, though immunotherapy and antibody-drug conjugates have expanded treatment considerably. Pathologists also increasingly report “HER2-low” and “HER2-ultralow” tumors, because some newer drugs work in these categories that were previously classified simply as HER2-negative.
Risk Factors
Being female and getting older are the two strongest risk factors for breast cancer. The large majority of breast cancers occur in women, though men can develop breast cancer too (roughly 2,800 cases each year in the U.S.). The median age at diagnosis is in the early 60s.
Genetic factors play a significant role. Inherited mutations in the BRCA1 and BRCA2 genes account for about 5 to 10 percent of breast cancers and carry a high lifetime risk. Other genes that raise risk include PALB2, TP53, PTEN, and CDH1. Family history matters even without an identified mutation – having one first-degree relative with breast cancer roughly doubles your risk. The USPSTF recommends risk assessment, genetic counseling, and potential BRCA testing for women whose personal or family history suggests an increased likelihood of a harmful mutation.
Hormonal and reproductive factors influence risk: early menstruation (before age 12), late menopause (after 55), first pregnancy after age 30, never having been pregnant, and menopausal hormone therapy (particularly combined estrogen-progestin therapy) all modestly increase risk. Modifiable risk factors include excess alcohol consumption (risk rises with each daily drink), excess body weight (particularly after menopause, when fat tissue becomes a primary estrogen source), physical inactivity, and prior chest radiation (for example, for Hodgkin lymphoma in young adulthood).
Symptoms and Early Detection
The most common presenting symptom of breast cancer is a painless lump or mass in the breast. According to the Mayo Clinic, other signs include thickening or swelling of part of the breast, skin dimpling or puckering, redness or flaky skin on the breast or nipple, nipple inversion (pulling inward), nipple discharge other than breast milk (especially if bloody), any change in breast size or shape, and pain in any area of the breast that does not resolve.
Inflammatory breast cancer deserves special mention because it presents differently – the breast may appear red, swollen, warm, and have a texture resembling an orange peel (peau d’orange) without a distinct lump. This aggressive subtype can be mistaken for a breast infection, delaying diagnosis, which is why the rapid changes described in the warning box above need urgent evaluation.
Breast self-awareness – being familiar with the normal look and feel of your breasts so you notice changes – is recommended by major cancer organizations. While formal monthly self-exams are no longer universally recommended due to high false-positive rates and lack of a proven mortality benefit, promptly reporting any new breast change to your doctor remains important.
Screening Guidelines
Screening mammography reduces breast cancer mortality by detecting cancers before they become symptomatic. Guidelines vary somewhat among organizations, reflecting different weighting of benefits versus harms (false positives, unnecessary biopsies, overdiagnosis).
The USPSTF updated its recommendation in 2024 to advise biennial (every-2-years) screening mammography for all women beginning at age 40 and continuing through age 74 (a Grade B recommendation) – a change from its prior guidance, which left the decision to start before 50 up to the individual. The American Cancer Society recommends women have the option to start annual mammography at 40, with annual screening recommended from 45 and the option to move to every 2 years at 55. The American College of Radiology recommends annual screening starting at age 40. These differences are one reason to discuss timing and frequency with your own clinician.
For women at higher-than-average risk – including BRCA mutation carriers, those with a strong family history, or those who received chest radiation before age 30 – enhanced screening with breast MRI in addition to mammography is recommended, often beginning at age 25 to 30. Risk-assessment tools such as the Tyrer-Cuzick model can help determine whether enhanced screening is appropriate for an individual patient.
Dense breast tissue, present in roughly 40 percent of women, both increases breast cancer risk and reduces mammographic sensitivity. As of 2024, the FDA requires that mammography reports nationwide notify patients whether their breasts are dense. The USPSTF concluded there is currently insufficient evidence to recommend for or against supplemental screening (ultrasound or MRI) specifically for women with dense breasts, so whether to add imaging is an individualized decision to make with your clinician. Understanding insurance coverage for screening can help remove financial barriers.
Diagnosis and Staging
When an abnormality is detected on screening or physical examination, diagnostic workup follows a structured approach. Diagnostic mammography provides additional targeted images. Ultrasound helps characterize masses – distinguishing solid from cystic lesions – and is the preferred initial imaging for women under 30. Breast MRI provides the most sensitive assessment but is not used as a first-line diagnostic tool due to its higher false-positive rate and cost.
Tissue diagnosis through biopsy is required before any treatment. Core needle biopsy, performed under image guidance (ultrasound or stereotactic), is the standard initial biopsy technique. It provides sufficient tissue for histologic diagnosis and receptor testing. Surgical (excisional) biopsy is reserved for cases where core biopsy is technically difficult or yields inconclusive results.
Staging involves assessing tumor size, lymph node involvement, and the presence of distant metastases using the TNM system. Imaging studies may include chest CT, bone scan, PET-CT, and brain MRI depending on the clinical scenario. Based on 2016-2022 SEER data, the National Cancer Institute’s SEER program reports 5-year relative survival of about 99-100 percent for localized disease, roughly 88 percent for regional (spread to nearby structures/nodes), and about 34 percent for distant (metastatic) disease – underscoring why early detection matters so much.
Treatment Options
Surgery
Surgical options include breast-conserving surgery (lumpectomy, removing the tumor with a margin of normal tissue) and mastectomy (removal of the entire breast). Multiple randomized trials have demonstrated equivalent survival between lumpectomy plus radiation and mastectomy for early-stage cancers. The choice depends on tumor size relative to breast size, number and location of tumors, patient preference, and ability to receive radiation therapy.
Sentinel lymph node biopsy – removing only the first one or two lymph nodes to which a breast cancer would drain – has largely replaced full axillary lymph node dissection for clinically node-negative patients, reducing the risk of lymphedema and other complications. Breast reconstruction, either immediate or delayed, using implants or a patient’s own tissue, is an option for women undergoing mastectomy.
Radiation Therapy
Radiation is standard after breast-conserving surgery, reducing local recurrence substantially. It may also be recommended after mastectomy for larger tumors or positive lymph nodes. Hypofractionated whole-breast radiation (shorter, more intense treatment delivered over about 3 to 4 weeks rather than 5 to 6) has become a standard option based on trials showing equivalent outcomes with greater convenience, and even shorter courses are used in selected patients.
Systemic Therapy
Systemic therapy – chemotherapy, hormone (endocrine) therapy, targeted therapy, and immunotherapy – is tailored to the molecular subtype and stage. HR-positive cancers are treated with endocrine therapy: tamoxifen for many premenopausal women and aromatase inhibitors (anastrozole, letrozole, exemestane) for postmenopausal women, typically for 5 to 10 years. CDK4/6 inhibitors (palbociclib, ribociclib, abemaciclib) added to endocrine therapy have significantly improved outcomes, and are now used both in advanced disease and in selected higher-risk early-stage cancers. For tumors with a PIK3CA or related mutation, targeted agents (such as PI3K/AKT-pathway inhibitors) have become additional options. All of these are clinician-directed, and dosing is individualized.
HER2-positive cancers are treated with HER2-targeted agents – trastuzumab (Herceptin) transformed treatment of this subtype, and agents such as pertuzumab, ado-trastuzumab emtansine (T-DM1), and the antibody-drug conjugate trastuzumab deruxtecan have further improved outcomes. Notably, trastuzumab deruxtecan is now also used in “HER2-low” and “HER2-ultralow” metastatic breast cancer, expanding who can benefit from HER2-directed therapy. According to the National Cancer Institute, the prognosis for HER2-positive breast cancer has improved dramatically since targeted therapy was introduced.
For triple-negative breast cancer, chemotherapy remains a backbone of treatment, but the immunotherapy drug pembrolizumab combined with chemotherapy is now standard for early-stage TNBC and for advanced TNBC that expresses PD-L1. Antibody-drug conjugates such as sacituzumab govitecan (for metastatic TNBC, and also used in certain HR-positive cancers) and, more recently, datopotamab deruxtecan (approved for certain HR-positive, HER2-negative metastatic cancers) have added further options. Genomic tests such as Oncotype DX and MammaPrint help identify which patients with HR-positive, node-negative cancer are likely to benefit from adding chemotherapy versus endocrine therapy alone.
Survivorship and Quality of Life
There are more than 4 million breast cancer survivors in the United States – a testament to improved treatment but also a reminder that survivorship brings its own challenges. Long-term and late effects of treatment can include lymphedema, cardiac effects from certain chemotherapy drugs and radiation, bone loss from aromatase inhibitors, menopausal symptoms, cognitive changes (“chemo brain”), fatigue, and emotional distress including anxiety about recurrence.
Survivorship care plans, recommended by the American Society of Clinical Oncology, outline treatment history, surveillance schedules, and management of long-term effects. Regular follow-up typically includes clinical examinations every 3 to 6 months for the first few years, then annually, plus annual mammography of the preserved and/or contralateral breast. Routine use of advanced imaging or blood tumor markers for surveillance is not recommended for asymptomatic survivors.
Exercise has been shown in multiple studies to reduce fatigue, improve mood, lower recurrence risk, and improve overall survival in breast cancer survivors. The American Cancer Society recommends at least 150 minutes of moderate or 75 minutes of vigorous physical activity per week for cancer survivors, along with maintaining a healthy weight and limiting alcohol.
Frequently Asked Questions
Can men get breast cancer?
Yes. While uncommon, roughly 2,800 men are diagnosed with breast cancer each year in the United States. Male breast cancer is usually detected as a painless lump beneath the nipple. Risk factors include older age, family history (particularly BRCA2 mutations), obesity, Klinefelter syndrome, and liver disease. Treatment parallels that for women and typically includes surgery and, when indicated, radiation, chemotherapy, HER2-targeted therapy, and endocrine therapy. Outcomes stage-for-stage are broadly comparable to those in women, though men are sometimes diagnosed later.
Does wearing an underwire bra cause breast cancer?
No. This is a persistent myth with no scientific evidence to support it. The American Cancer Society and other medical organizations have stated that bra type, tightness, or underwire does not increase breast cancer risk. This claim originated from a non-peer-reviewed book and has been repeatedly debunked.
What does a breast cancer lump feel like?
Breast cancer lumps are often hard, irregular in shape, and painless, though they can vary in presentation. Some feel rounded and firm. Inflammatory breast cancer may not produce a lump at all. Normal breast tissue can feel lumpy, particularly before menstruation, which is why knowing your baseline is important. Any new lump or mass that persists through a menstrual cycle, feels distinctly different from surrounding tissue, or is progressively growing should be evaluated by your doctor.
How effective is mammography at detecting breast cancer?
Mammography detects roughly 84 to 87 percent of breast cancers in women who are screened. Sensitivity is higher in women with fatty breast tissue and lower in women with dense breast tissue. 3D mammography (tomosynthesis) improves detection and reduces call-backs compared with 2D mammography alone and is now widely used as the standard screening tool. For high-risk women, adding breast MRI increases sensitivity substantially.
Should I get genetic testing for breast cancer?
Genetic counseling and testing are recommended if you have a strong family history of breast or ovarian cancer, a relative with a known gene mutation, breast cancer diagnosed before age 50, triple-negative breast cancer, bilateral breast cancer, or Ashkenazi Jewish ancestry (associated with higher rates of BRCA mutations). Your doctor or a genetic counselor can perform a risk assessment and determine whether testing is appropriate for your situation.
Taking Charge of Your Breast Health
Regardless of your risk level, proactive steps make a difference. Talk with your clinician about starting screening mammography by age 40 – and about how often you should be screened – rather than waiting for the topic to come up. If you have a family history that concerns you, seek a formal risk assessment. Many breast centers offer high-risk clinics that provide personalized screening and prevention plans.
Modifiable risk factors matter too. Maintaining a healthy weight (particularly after menopause), staying physically active, moderating alcohol intake, and discussing the risks and benefits of menopausal hormone therapy with your doctor are all evidence-based strategies. For selected very-high-risk women, risk-reducing medications (such as tamoxifen, raloxifene, or an aromatase inhibitor) can meaningfully lower breast cancer risk, and risk-reducing mastectomy is an option for some BRCA carriers – these are individualized decisions made with your care team.
If you are diagnosed with breast cancer, seek care from a multidisciplinary team at a center experienced in breast cancer treatment. Ask about your tumor’s molecular profile – it directly determines which treatments will be most effective. Explore clinical trials if appropriate. And remember that breast cancer treatment has never been more effective or more personalized than it is today.
Sources
- American Cancer Society – How Common Is Breast Cancer? (current-year estimates) and treatment/survivorship resources
- U.S. Preventive Services Task Force – Breast Cancer: Screening (2024 recommendation)
- National Cancer Institute / SEER – Female Breast Cancer statistics (2016-2022 data)
- Mayo Clinic – Breast Cancer: Symptoms and Causes
- U.S. Food and Drug Administration – breast cancer drug approvals (antibody-drug conjugates, targeted and immunotherapy agents)
- American Society of Clinical Oncology (ASCO) – survivorship and follow-up guidance