Breast cancer: risk factors
- Topic
Breast cancer is the most common cancer in women; the biggest risks are being female and getting older, with hormones, genes and lifestyle adding to them.
What it is
Breast cancer is the most common cancer in women worldwide and in Colombia, and one of the leading causes of cancer death in women. The strongest risk factors are female sex and age. Inherited mutations, a close relative with breast cancer and atypical hyperplasia raise risk sharply; prolonged exposure to estrogen, through early menarche, late menopause, nulliparity, late first pregnancy, postmenopausal obesity or combined hormone therapy, raises it moderately. Breast density, chest radiation at a young age and alcohol also contribute, while early pregnancy, breastfeeding and physical activity lower risk.
Key facts
- About one in ten breast cancers is attributed to a single inherited high-risk gene.
- Pregnancy causes terminal differentiation of breast epithelium, which may explain its protective effect when early.
- In Latin America, breast cancer is diagnosed at later stages than in high-income countries, which worsens survival.
Risk factors by how they act
| Group | Factors | How they raise risk |
|---|---|---|
| Inherited | BRCA1, BRCA2, TP53, PTEN, PALB2, CHEK2, family history | Defective DNA repair or growth control in every cell |
| Hormonal | Early menarche, late menopause, nulliparity, late first birth, hormone therapy | More cycles and years of estrogen-driven proliferation |
| Metabolic and lifestyle | Postmenopausal obesity, alcohol, inactivity | Aromatase in fat, higher estrogen, other growth signals |
| Tissue | Dense breasts, atypical hyperplasia, previous breast cancer | More epithelium at risk, clonal precursors |
| Environmental | Chest radiation in childhood or youth | DNA damage in developing breast tissue |
Clinical notes
- Risk models combine age, family history, reproductive history, biopsies and density to guide screening and prevention.
- Women at very high risk are offered genetic counselling, MRI screening and risk-reducing options.
Test yourself
Think of the answer, then tap the question to see it.
What are the two strongest risk factors for breast cancer?
Female sex and increasing age.
How does obesity after menopause raise breast cancer risk?
Aromatase in adipose tissue converts androgens to estrogen, the main source of estrogen after menopause.
Which reproductive factors protect against breast cancer?
An early full-term first pregnancy and breastfeeding.
Elsewhere in DurgiPedia
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Breast cancer: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Stage at diagnosis and stage-specific survival of breast cancer in Latin America and the Caribbean: A systematic review and meta-analysis (PloS one, 2019).
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Representative model, for educational purposes only.