Breast Cancer Risk Factors: What Matters, and What Can You Change?

The question “Why did this happen to me?” often has no single answer. Breast cancer arises from several factors coming together; in many patients no clear cause can be found. Even so, knowing the risk factors is valuable both for planning screening and for lifestyle choices.

Factors that cannot be changed

• Being a woman, and age: risk rises with age; most diagnoses are made after 50.
• Family history: breast or ovarian cancer in a first-degree relative (mother, sister, daughter) increases risk.
• Genetic changes: the best known are BRCA1 and BRCA2; also genes such as PALB2, TP53, CHEK2.
• Dense breast tissue and a history of some benign breast conditions (such as atypical hyperplasia).
• Hormonal span: early periods and late menopause mean a longer exposure to oestrogen.

Factors we can influence

• Alcohol: alcohol, like several other cancers, is linked with breast cancer, and the risk rises as the amount increases. There is no “safe” lower limit; cutting down reduces risk.
• Excess weight: especially after menopause, risk rises because of oestrogen produced by fat tissue.
• Physical activity: regular activity lowers risk both before and after menopause. At least 150 minutes of moderate activity a week is recommended.
• Breastfeeding: a slight protective effect is seen as total breastfeeding time lengthens.
• Menopausal hormone therapy: especially oestrogen-plus-progestogen combinations may raise risk; the reason for use and its duration should be reviewed with your doctor.
• Smoking: shown to be harmful for breast cancer too, and should be stopped for general health.

What is knowing your risk good for?

In women at high risk, a surveillance plan can be made that starts at an earlier age and includes MRI; genetic counselling and, if needed, preventive options can be discussed. If risk is low, keeping up the screening schedule is still important: the great majority of women with breast cancer have no clear risk factor.