Breast Cancer Causes

Breast cancer starts when cells in the breast begin growing uncontrollably. Why it happens to one woman and not another is usually unanswerable - but medicine does know the factors that shift the odds, and which of them you can influence.

Factors you cannot change

• Being a woman and getting older: the two biggest factors; risk rises steeply after 50 (men get breast cancer too - rarely, about 1 in 100 cases)
• Family history and inherited genes: BRCA1 and BRCA2 mutations strongly raise risk; a mother, sister or daughter with breast or ovarian cancer matters - tell your doctor
• Dense breast tissue: both raises risk and makes mammograms harder to read
• Hormonal history: early periods (before 12), late menopause (after 55), never having children or a first child after 30 - all mean longer lifetime estrogen exposure
• Previous chest radiation (for example, treatment for another cancer in youth)
• A previous breast cancer or certain benign breast conditions

Factors you can influence

• Alcohol: even moderate regular drinking raises risk; less is better
• Weight after menopause: postmenopausal obesity raises risk through estrogen from fat tissue
• Physical inactivity: regular exercise lowers risk
• Combined hormone replacement therapy (HRT): long-term combined HRT raises risk; decisions about HRT should be made with a doctor, weighing menopause symptoms against this
• Breastfeeding: each year of breastfeeding modestly lowers risk

What does not cause it

Underwire bras, deodorants, breast implants (a rare separate lymphoma aside), blows or injuries to the breast, and stress do not cause breast cancer - the myths deserve to be retired. A breast injury can, however, draw attention to a lump that was already there, which is why injury-found lumps still get checked.

The classical frame - honest limits

Classical texts described breast swellings (Stana Granthi) and breast tumors (Stana Arbuda) and blamed heavy, channel-blocking food, suppressed lactation, chest trauma and dosha imbalance (Sushruta Samhita, Nidana Sthana 10; Madhava Nidana 56). They had no concept of hormones, genes or mammography. The honest position: causes and risk are modern medical territory; the classical frame explains tradition, not etiology.