Overview
Breast cancer occurs when cells in breast tissue grow in an abnormal, uncontrolled way. It is one of the most common cancers in the UK. Many breast cancers are detected early when they are more treatable. Outcomes depend on the type, stage and available treatment.
How common is it?
Around 59,400 people were diagnosed with invasive breast cancer each year in the UK on average in 2019 and 2021-2022. It is much more common in women, but men can also develop it.
Causes and risk factors
Most breast cancers result from a combination of ageing, hormonal exposure, lifestyle factors, and genetic susceptibility. Inherited BRCA1 and BRCA2 gene faults carry a significantly elevated lifetime risk.
Common risk factors
- Age (risk rises sharply after 50)
- Family history especially first-degree relatives
- BRCA1 or BRCA2 gene variants
- Previous breast cancer or atypical cells on biopsy
- Long use of combined HRT
- Alcohol consumption
- Obesity after menopause
- Having children late or not breastfeeding
Symptoms
- A new lump in the breast, chest or armpit, whether painful or painless
- Change in breast shape or size
- Dimpling or puckering of skin
- Nipple inversion or discharge (especially if blood-stained)
- Rash or redness over the breast skin
- Persistent pain in one area of the breast
When to see a doctor
Contact a GP about a new lump in the breast, chest or armpit, nipple inversion or discharge, skin dimpling, or another breast change that is not normal for you. Do not wait two weeks before reporting it. Many changes are not cancer, but they still need assessment; the clinician will decide whether referral to a breast clinic is appropriate.
Diagnosis
Triple assessment: clinical examination, mammogram or ultrasound, and core needle biopsy. MRI is used in high-risk women and for staging. Hormone receptor and HER2 status on biopsy determines which treatments will work best.
Treatments
Surgery
Lumpectomy removes the tumour with a margin of normal tissue. Mastectomy removes the whole breast. Sentinel lymph node biopsy checks whether cancer has spread to lymph nodes.
Radiotherapy
Radiotherapy is often offered after breast-conserving surgery to reduce the risk of cancer returning. Whether it is needed depends on the cancer and the individual's circumstances.
Systemic therapy
Hormone therapy (tamoxifen, aromatase inhibitors) for oestrogen-positive cancers. Chemotherapy for aggressive or spread cancers. HER2-targeted drugs (trastuzumab) for HER2-positive cancers.
Self-care and lifestyle
- Attend NHS breast screening from age 50 (or earlier if high risk)
- Limit alcohol, maintain healthy weight, and exercise regularly
- Breastfeeding reduces breast cancer risk
- Know what your breasts normally look and feel like so you notice changes promptly
Prevention
Regular exercise, limiting alcohol, maintaining healthy weight, and breastfeeding modestly reduce risk. Women with high genetic risk may be offered risk-reducing surgery or preventive medication.
Sources for targeted updates
Updated: 24 October 2026. Targeted corrections to overview, frequency, symptoms, treatment, key facts. This update covers the named sections; a full review of the remaining guide is pending.