Breast cancer is the most common cancer affecting women worldwide and remains a major cause of cancer-related death. According to the World Health Organization, an estimated 2.4 million women were diagnosed with breast cancer globally in 2024.
Despite this burden, advances in screening, diagnosis, and treatment have significantly improved outcomes. Earlier detection can provide more treatment options and is generally associated with better outcomes.
This is where breast cancer screening plays an important role.
What Is Breast Cancer Screening?
Breast cancer screening is the process of examining people who have no symptoms of breast cancer in order to identify disease at an earlier stage.
The aim is to detect cancer before it causes symptoms or progresses further.
Most organised screening programmes use mammography, a specialised low-dose X-ray examination of the breast. Mammograms can identify abnormalities that may be too small to feel during a clinical examination.
By identifying some breast cancers earlier, screening can improve treatment options and reduce deaths from breast cancer.
Why Is Early Detection Important?
The stage at which breast cancer is diagnosed is an important factor influencing treatment and prognosis. When breast cancer is found at an earlier stage:
- Treatment may be less extensive
- Breast-conserving surgery may be possible in appropriate cases
- More treatment options may be available
- Outcomes and survival are generally better
Many breast cancers detected through screening are found before symptoms develop, providing an opportunity for earlier assessment and treatment.
Breast Screening Around the World
Many countries have established organised breast cancer screening programmes, although eligibility criteria and screening intervals vary between healthcare systems.
Examples include:
- The United Kingdom, which provides routine mammographic screening through the NHS Breast Screening Programme
- European countries with organised population-based screening programmes
- Canada and Australia, where organised screening is delivered through national, provincial, territorial, or regional programmes
- The United States, where screening recommendations vary between professional organisations and individual risk is also considered
Some healthcare systems also provide opportunistic screening, where mammography is arranged through routine healthcare rather than a central population-based programme.
Regardless of the specific approach, the underlying principle is to identify breast cancer before symptoms develop whenever appropriate.
The NHS Breast Screening Programme: An Example
One of the largest established screening programmes is the NHS Breast Screening Programme in England.
NHS breast screening is offered from age 50 up to a person’s 71st birthday. The first invitation is usually sent between the ages of 50 and 53, followed by an invitation every three years until the 71st birthday. People aged 71 and over are not automatically invited but can contact their local breast screening service about further screening.
What Happens During a Mammogram?
A mammogram is a relatively quick procedure performed by trained healthcare professionals.
During the examination:
- Each breast is positioned on the mammography machine
- The breast is compressed briefly to obtain clear images
- X-ray images are taken from different angles
The appointment usually takes less than 30 minutes.
Some people experience temporary discomfort during compression, but this usually lasts only while the image is being taken.
The mammograms are then reviewed by trained breast screening image readers.
What Happens If an Abnormality Is Found?
Being recalled after a screening mammogram does not necessarily mean that breast cancer is present.
Many findings detected during screening ultimately prove to be benign breast changes. Further assessment may nevertheless be needed to determine what the finding represents.
Within the NHS Breast Screening Programme, assessment of a potentially significant abnormality follows the triple assessment model, combining clinical examination, appropriate imaging, and needle biopsy when indicated.
Understanding the Triple Assessment
Triple assessment is a well-established approach for evaluating suspected breast abnormalities. It brings together clinical findings, imaging, and tissue sampling when required so that the information can be interpreted together.
1. Clinical Assessment
The clinical component may include:
- Reviewing symptoms and medical history
- Discussing family history and relevant risk factors
- Physical examination of the breasts
- Examination of regional lymph nodes when appropriate
2. Radiological Assessment
The imaging component depends on the person’s age, symptoms, screening findings, and clinical circumstances.
It may include:
- Mammography or additional mammographic views
- Breast ultrasound
- Digital breast tomosynthesis or other additional imaging when appropriate
- Breast MRI in selected cases
Radiological assessment helps specialists evaluate the location, size, appearance, and other characteristics of an abnormality and determine whether further investigation is needed.
3. Pathological Assessment
When tissue sampling is indicated, pathological assessment can provide a definitive tissue diagnosis.
A needle biopsy may be performed to obtain a sample of tissue for examination by a pathologist.
Pathology can help determine:
- Whether a sampled lesion is benign or malignant
- The specific type of breast cancer, when cancer is present
- Tumour grade
- Relevant biomarkers that may help guide treatment decisions
Why Is Triple Assessment So Effective?
Each component contributes different information:
- Clinical examination assesses physical signs and symptoms
- Imaging evaluates the internal appearance of the breast
- Pathology examines sampled tissue at a microscopic and molecular level when biopsy is required
The results are interpreted together. If clinical, imaging, and pathological findings are not consistent with one another, additional assessment may be needed before a final diagnosis is made.
When Should You Seek Medical Advice?
Breast screening is intended for people who do not have symptoms. Breast cancer can, however, develop between screening appointments, and symptoms can also occur in people who are not yet eligible for routine screening.
You should seek medical advice if you notice a new or unusual breast change, including:
- A new lump or thickening in the breast or armpit
- A change in the size or shape of the breast
- Dimpling, puckering, or persistent redness of the skin
- A new change to the nipple, including inversion
- Unexplained nipple discharge, particularly if blood-stained
- Persistent breast or nipple pain affecting one area
- A rash, scaling, or crusting around the nipple
- Swelling in the armpit or around the collarbone
Most breast changes are not caused by cancer, but new or persistent symptoms should be assessed by a healthcare professional.
Do not wait for your next screening appointment if you develop symptoms. Screening is intended for people without symptoms, while a new breast change may require diagnostic assessment regardless of age or the timing of the most recent mammogram.
Key Take-Home Messages
- Breast cancer is the most commonly diagnosed cancer among women worldwide
- Earlier detection can improve treatment options and outcomes
- Mammography is the principal imaging test used in organised breast cancer screening
- Screening recommendations and eligibility differ between countries and healthcare systems
- The NHS Breast Screening Programme offers routine mammographic screening every three years from age 50 up to the 71st birthday
- Screen-detected abnormalities may be evaluated using triple assessment: clinical examination, imaging, and needle biopsy when indicated
- People with new breast symptoms should seek medical assessment rather than waiting for their next screening appointment
References
- World Health Organization. Breast cancer. Updated July 2026. WHO fact sheet
- NHS. Who breast screening is for. NHS breast screening guidance
- NHS England. Clinical guidance for breast cancer screening assessment. Updated January 2026. NHS England clinical guidance
- National Institute for Health and Care Excellence (NICE). Breast cancer quality standard QS12: Timely diagnosis. NICE guidance
