Breast Cancer

What it is

Overview

Breast cancer occurs when cells in the breast grow uncontrollably. It can form in different parts of the breast — most often in the ducts or lobules. It affects primarily women but can occur in men. Early detection through screening has dramatically improved survival rates over the past decades.

Biology

How It Develops

Breast cancer begins when DNA mutations cause normal breast cells to grow and divide uncontrollably. These mutations can be inherited (BRCA1/BRCA2 genes) or acquired over a lifetime through hormonal exposure, radiation, or unknown factors. The cells form a tumor that can invade surrounding tissue and spread to lymph nodes or distant organs.

Warning signs

Symptoms

• —New lump or mass in the breast or underarm
• —Swelling, thickening, or changes in breast shape
• —Skin irritation or dimpling (peau d'orange)
• —Nipple pain or retraction (turning inward)
• —Nipple discharge other than breast milk
• —Redness or flaky skin on the breast or nipple

Detection

Diagnosis Methods

• —Mammography (screening and diagnostic)
• —Breast ultrasound
• —MRI for high-risk individuals
• —Biopsy (core needle or surgical)
• —Genetic testing for BRCA mutations
• —PET or bone scan for staging

Medical care

Treatment Options

• —Surgery (lumpectomy or mastectomy)
• —Radiation therapy
• —Chemotherapy
• —Hormone therapy (tamoxifen, aromatase inhibitors)
• —Targeted therapy (HER2-positive: trastuzumab/Herceptin)
• —Immunotherapy

Data

Statistics

Prevention

Risk Factors

• —Female sex and increasing age
• —BRCA1 or BRCA2 gene mutations
• —Dense breast tissue
• —Previous breast cancer or radiation
• —Hormone replacement therapy
• —Obesity and alcohol use

Further reading

Resources