Overview
Breast cancer is a type of cancer caused by the uncontrolled growth of cells in breast tissue. It is the most common cancer in women; about 1 in 8 women may face breast cancer during her lifetime. When diagnosed early, treatment success exceeds 95%.
It is rarely seen in men (about 1% of breast cancer cases).
Symptoms
The most common symptom is a palpable lump in the breast. However, breast cancer can have many different symptoms:
- A hard, palpable lump in the breast or armpit
- Change in the shape or size of the breast
- Skin dimpling, orange peel appearance, redness
- Inverted nipple
- Bloody or clear discharge from the nipple
- Pain in the breast or nipple (rare)
- Scaling, crusting of the breast skin
- Swelling in the armpit (enlarged lymph nodes)
There may be no symptoms in early stages; that is why screening is important.
Causes
Breast cancer is caused by changes (mutations) in the DNA of breast cells. There is no single cause; genetic, hormonal, and environmental factors interact.
Risk Factors
Non-modifiable risk factors:
- Being female (largest risk factor)
- Age (over 50)
- Family history (mother, sister, daughter with breast cancer)
- Genetic mutations: BRCA1, BRCA2 genes
- Early menstruation, late menopause
- Never having given birth or first birth after age 30
- Previous breast or ovarian cancer
- Dense breast tissue
- History of radiation therapy to the chest
Modifiable risk factors:
- Excess weight (especially after menopause)
- Sedentary lifestyle
- Alcohol use
- Smoking
- Hormone replacement therapy (long-term)
- Not breastfeeding
Complications
- Metastasis: Spread to bones, lungs, liver, brain
- Lymphedema (arm swelling after surgery)
- Early menopause (due to chemotherapy)
- Psychological effects: Depression, anxiety
- Risk of recurrence
When to See a Doctor
- If you notice a new lump or change in your breast
- If you have nipple discharge
- If you notice skin changes
- If you feel a lump in your armpit
Screening recommendations:
- Ages 20-39: Monthly self-exam + clinical breast exam every 3 years
- Age 40 and above: Annual mammography + clinical exam
- High-risk women: MRI screening from age 30
Diagnosis and Treatment
Diagnosis:
- Mammography, ultrasound, breast MRI
- Needle biopsy (definitive diagnosis)
- Hormone and HER2 receptor testing
- Genetic testing (when needed)
- Staging imaging (CT, PET)
Treatment (based on stage and tumor characteristics):
- Surgery: Lumpectomy (tumor only), mastectomy (entire breast)
- Radiation therapy
- Chemotherapy
- Hormone therapy: Tamoxifen, aromatase inhibitors (in hormone-receptor-positive tumors)
- Targeted therapy: Trastuzumab (Herceptin) — in HER2-positive tumors
- Immunotherapy
Treatment is usually planned by a multidisciplinary team.
Prevention
- Get screened regularly (most critical protective measure)
- Maintain a healthy weight
- Exercise regularly (at least 150 minutes per week)
- Limit alcohol consumption
- Quit smoking
- Breastfeed for 6 months or longer if possible
- Avoid long-term hormone replacement therapy
- Follow a vegetable- and fruit-based, less-processed diet
- Consider genetic counseling if you have a family history