Breast cancer

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC

A common form of cancer originating in breast tissue

Breast cancer
Synonyms	Breast carcinoma
Pronounce	N/A
Field	Oncology
Symptoms	Breast lump, breast pain, nipple discharge, changes in skin
Complications	Metastasis, lymphedema, recurrence
Onset	Variable; more common after age 40
Duration	N/A
Types	N/A
Causes	Multifactorial: genetics, hormonal, environmental factors
Risks	Female sex, age, BRCA mutations, family history, hormone therapy, obesity, alcohol
Diagnosis	Mammography, ultrasound, biopsy, MRI
Differential diagnosis	N/A
Prevention	N/A
Treatment	Surgery, radiation therapy, chemotherapy, targeted therapy, hormonal therapy
Medication	N/A
Prognosis	Generally good if detected early
Frequency	1 in 8 women (lifetime risk)
Deaths	N/A

Breast cancer is a malignant tumor that originates in the cells of the breast tissue. It is the most common cancer among women worldwide and the second leading cause of cancer-related death in women after lung cancer. Though rare, it can also affect men. Early detection, accurate diagnosis, and timely treatment are crucial for improving survival outcomes.

Diagram of early signs of breast cancer

Mammogram image showing tumor

Historical Background

Breast cancer has been known for millennia. Descriptions of tumors believed to be breast cancer appear in the Edwin Smith Papyrus from ancient Egypt, dating to around 1600 BCE. Early treatments were mostly surgical, and until the 19th century, options were limited. The modern surgical era began with William Stewart Halsted's radical mastectomy technique in the 1880s. Since then, approaches have evolved to include lumpectomy, chemotherapy, radiotherapy, and targeted therapy.

Types

Breast cancer can present in different forms. The main types include:

• Ductal carcinoma in situ (DCIS): Non-invasive; confined to milk ducts.
• Lobular carcinoma in situ (LCIS): Abnormal cells in the lobules; a marker for increased risk.
• Invasive ductal carcinoma: Cancer has spread beyond ducts; most common type.
• Invasive lobular carcinoma: Begins in lobules and invades nearby tissue.
• Inflammatory breast cancer: Rare and aggressive; presents with redness and swelling.
• Paget's disease of the breast: Affects the nipple; often associated with underlying carcinoma.
• Triple-negative breast cancer: Lacks estrogen, progesterone, and HER2 receptors; often more aggressive.

Causes and Risk Factors

The exact cause is unknown, but several risk factors increase the likelihood of developing breast cancer:

• Female gender
• Age over 50
• Family history (especially with BRCA1 or BRCA2 mutations)
• Long-term exposure to estrogen
• Early menstruation (before age 12) or late menopause (after age 55)
• Lack of pregnancy or late pregnancy
• Use of hormone replacement therapy
• Obesity and physical inactivity
• Alcohol consumption
• Previous history of breast abnormalities or biopsies
• Radiation exposure to the chest

Symptoms

Signs of breast cancer may include:

• A lump or mass in the breast or underarm
• Change in the size or shape of the breast
• Nipple retraction, discharge (especially bloody)
• Skin changes: dimpling, redness, or texture resembling an orange peel
• Pain in the breast or nipple area (less common)

These symptoms can also be caused by benign conditions such as fibrocystic breast disease or mastitis.

Diagnosis

Diagnosis involves a combination of clinical and imaging techniques:

• Clinical breast examination – Manual palpation by a healthcare provider
• Mammography – X-ray imaging to detect tumors
• Ultrasound – Useful in distinguishing solid from cystic masses
• MRI – Used in high-risk women or ambiguous cases
• Biopsy – Definitive diagnosis via fine needle aspiration, core needle biopsy, or surgical excision

Needle biopsy under guidance

Staging

Breast cancer is staged from 0 to IV using the TNM staging system:

• Stage 0: DCIS or LCIS
• Stage I–III: Local or regional spread
• Stage IV: Metastatic cancer; spread to distant organs such as bone, liver, lungs, or brain

Stage I

Stage IV

Treatment

Treatment plans depend on the type, stage, hormone receptor status, and patient preferences.

Surgical Options

• Lumpectomy – Removal of tumor with margin of normal tissue
• Mastectomy – Removal of one or both breasts
• Sentinel lymph node biopsy – Identifies first lymph nodes cancer may spread to
• Axillary lymph node dissection – Removes lymph nodes for staging and treatment

Post-mastectomy

Post-reconstruction

Radiation Therapy

Usually follows surgery to reduce recurrence:

• External beam radiation
• Internal radiation (brachytherapy)

Chemotherapy

Drugs like doxorubicin, cyclophosphamide, paclitaxel target rapidly dividing cells. Used before (neoadjuvant) or after (adjuvant) surgery.

Hormonal Therapy

Used for estrogen receptor (ER)-positive cancers:

• Tamoxifen – selective estrogen receptor modulator (SERM)
• Aromatase inhibitors – such as letrozole, anastrozole

Targeted Therapy

Used in HER2-positive cancers:

• Trastuzumab (Herceptin)
• Pertuzumab
• T-DM1

Prognosis

Prognosis varies with the stage and subtype:

• 5-year survival rate:
  • Nearly 99% for localized Stage I
  • Around 28% for metastatic Stage IV

Other factors influencing outcome include tumor size, lymph node involvement, receptor status, and response to treatment.

Prevention

There is no sure way to prevent breast cancer, but steps can reduce risk:

• Maintain healthy weight and active lifestyle
• Limit alcohol intake
• Avoid long-term hormone replacement therapy
• Breastfeed if possible
• Regular screening mammograms beginning at age 40–50
• Breast self-examination and annual clinical breast exams
• Genetic counseling and testing for high-risk individuals

Breast Cancer in Men

Though rare, men can develop breast cancer. Risk factors include age, Klinefelter syndrome, radiation exposure, BRCA2 mutations, and liver disease. Symptoms and treatment are similar to those in women.

Breast Reconstruction

Women who undergo mastectomy may choose breast reconstruction surgery using:

• Breast implants
• Autologous tissue transfer (e.g., DIEP flap)
• Combination of both

Support and Resources

Living with breast cancer can be physically and emotionally challenging. Support groups, counseling, and survivorship programs are essential components of care.

Related Articles

• Mammography
• Cancer staging
• Chemotherapy
• Oncology
• Breast reconstruction
• Genetic testing
• Lymph nodes
• Triple-negative breast cancer
• Hormone therapy
• HER2

External Links

• National Cancer Institute – Breast Cancer
• BreastCancer.org
• American Cancer Society – Breast Cancer