Breast Cancer in Your 20s, 30s and Under 50 — What Young Women Need to Know

How common is breast cancer in young women?

Breast cancer in women under 40 is rare, accounting for around 5% of UK cases. In women aged 40–49, it accounts for around 15% of cases. Together, women under 50 account for roughly 20% of all breast cancer diagnoses in the UK each year — around 11,000 women.

Why it can be different

Breast cancers in younger women are more likely to be high-grade and hormone receptor-negative (including triple-negative). They are also more likely to be associated with BRCA1 or BRCA2 gene mutations. Because younger women are not routinely screened by mammogram in the UK, their cancers are more likely to be self-detected or found incidentally, sometimes at a later stage.

Dense breast tissue — which is more common in younger women — makes mammograms less effective. MRI is more sensitive and is used for high-risk young women.

Genetics and family history

A diagnosis of breast cancer under 40 significantly raises the probability of an inherited gene mutation. Women diagnosed young should discuss genetic referral with their oncologist. If a BRCA mutation is identified, family members may also wish to be tested.

Fertility and treatment

Many chemotherapy regimens carry a risk of temporary or permanent fertility effects. If you may wish to have children in the future, it is very important to discuss fertility preservation before starting chemotherapy. Options include embryo or egg freezing. In the UK, this should be offered as part of the treatment planning process.

Life with breast cancer under 50

A breast cancer diagnosis can affect young women's lives in particular ways — career, relationships, fertility, identity and the menopause effects of treatment. Specialist nurses, psychological support, and peer support groups are important parts of comprehensive care.