Breast screening 101 – Types of breast screening and how they work

For many Singaporean women, breast cancer develops long before noticing any signs or symptoms. For others, there may be no signs or symptoms at all.¹

With breast cancer the most common cancer type in women, accounting for over 11 000 cases between 2014-2018,² it is essential to stay aware of breast cancer even if you see no changes in your body. This includes receiving regular breast screening, where early detection is linked with a greater chance of survival. But what is involved in a breast screening and what options are available to you?

Types of breast screening

Although breast screening cannot prevent breast cancer, it can help detect breast cancer early when it is still small and contained. This offers the opportunity for you to get early treatment and better outcomes.

There are two main types of breast screening tools with varying functions – mammogram and ultrasound. However, the mammogram is the primary screening method offered in Singapore, with ultrasounds providing a more comprehensive picture of your breast – often being used in conjunction with a mammogram to tell the difference between masses or guide a future biopsy.

Mammograms

A mammogram is a screening procedure that uses low dose x-rays to examine changes and abnormalities in your breast tissue, such as tiny white spots of calcium (called calcifications) or masses even before they can be felt.³ It does this by compressing each breast between the x-ray machine’s two plates. The process is repeated for each breast, capturing digital images in only a few seconds.

If the results show any abnormalities, your health screening physician may order additional tests such as a repeat mammogram and an ultrasound scan. An abnormal mammogram does not always mean that a woman has breast cancer. However, if the results are suspicious, you will be referred to the breast specialist for further evaluation.

Ultrasounds

An ultrasound sends high-speed sound waves through your breast to assess masses or other suspicious areas (often found in a mammogram).⁴ During this process, an ultrasound technician will move a device known as a transducer over your skin, converting its readings into pictures.

In the case where a lump is located, an ultrasound can determine if the lump is solid or filled with fluid (cyst).⁵ These solid masses have the potential to be cancer.

Which breast screening is best for me?

When it comes to screening for breast cancer, mammogram is still the ‘gold standard’ and offers the most accurate option for breast screening. This is due to the mammograms’ ability to see both calcifications and masses, unlike ultrasounds that cannot find calcifications. Mammograms can also offer clearer and better-defined images to detect abnormalities.

However, when it comes to mammograms, it is harder to detect cancers in very dense breasts with a higher fibrous and glandular tissue distribution. This makes mammograms less effective in women aged under 40, when breast density is higher. It also poses a potential problem for Singaporean women of Asian ethnicity, with Asian women often having denser breasts.⁶ In these situations, receiving both a mammogram and ultrasound is the most effective option to ensure breast abnormalities are identified that the mammogram cannot see.

Ultrasounds provide the added benefit of not using radiation. This offers an option for pregnant women, who are unable to receive a mammogram due to the radiation’s potential impact on the unborn baby.