Mammogram (screening)

Category: Screening Tests · All screening tests

What it is

A screening mammogram is a low-dose X-ray of the breast offered to women without symptoms, typically every three years between about 50 and 70 in the UK programme (ages and intervals vary by country), to find cancers too small to feel. Each breast is compressed briefly between plates and imaged from two angles.

Why it is done

Population screening reduces deaths from breast cancer by finding cancers early. Women at higher inherited risk may start earlier with additional MRI screening under specialist programmes.

How to prepare

Wear a separate top for easy undressing from the waist up. Do not use talcum powder or spray deodorant on the day (they can mimic calcifications). Tell the mammographer about implants, previous breast surgery and any new symptoms — new symptoms need a symptomatic clinic, not screening.

What happens during the procedure

You stand at the machine; each breast is positioned and compressed firmly for a few seconds per image — uncomfortable, occasionally painful, but brief. The appointment takes about 10 minutes. Four images are standard (two per breast).

Afterwards — recovery & results

Results come by letter, usually within two to three weeks. Most are normal. A small proportion are recalled for assessment (more images, ultrasound, sometimes biopsy) — most recalls turn out not to be cancer. Any symptoms developing between screens should be checked promptly rather than waiting for the next round.

Risks & considerations

Mammography uses a small radiation dose. Harms of screening include false alarms, and overdiagnosis — finding cancers that would never have caused harm, which cannot be distinguished at diagnosis. Compression discomfort is the commonest immediate issue. The programme provides balanced information so you can decide.

Frequently asked questions

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