Mammography is the X-ray imaging that is used to screen for abnormalities in the breast. Mammography plays a key role in the early detection and treatment of breast cancer and helps to reduce the number of deaths caused by the disease.

Mammography screening is recommended for all women over the age of 40 years or for younger women who have a family history of breast cancer.

How does mammography work?

For a mammogram to be taken, the breast is squeezed and spread out between two hard, flat plates. The mammogram then produces black and white X-ray images of the breast which can be displayed on a computer screen and assessed by an expert in breast cancer.

Mammograms are very accurate but can still sometimes miss cancer. Therefore, all women are advised to have a clinical breast exam (CBE) in which the appearance and feel of the breasts is checked by a healthcare provider who is trained in breast examination.

During a CBE, the armpits are also checked for the presence of lumps and other changes. Women should have a clinical breast exam every 3 years starting from the age of 20 years and every year after the age of 40.

Timing of mammography

Mammography may be mildly painful or uncomfortable and is best avoided before periods when the breasts are more sensitive. An ideal time for a mammography is a week after the last period finished, when the breasts are less tender.

On the day of mammography, it is advisable not to wear antiperspirants, perfumes, lotions, powders, deodorants or jewellery as these can interfere with the images produced.

The patient is asked to place the breast between two plastic plates which press gently on the breast to flatten it. The pressure lasts for around a few seconds and two images of each breast are taken - one from the side and another from above. The whole procedure takes around 15 minutes.

What happens afterwards?

If a breast lump is detected via mammography, further tests are advised including a fine needle aspiration or a biopsy for confirmation of the diagnosis and commencement of treatment. The mammogram also shows how dense the breast tissue is.

While some breasts have more fatty tissue than fibrous and glandular, others have the opposite. The former are termed low density breasts and the latter high density breasts. High density breast tissue is more at risk of breast cancer.