• A mammogram is able to detect microcalcifications, which are tiny dots of calcification seen in early breast cancer.
• Studies have shown that cancers detected during screening have a favourable outcome compared to clinically detected cancers, which is breast cancer that can be felt as a lump on clinical examination.
• Early breast cancer is curable with cure rates approaching 100 per cent.

“A mammogram is not fail-proof and a small number of breast cancer cases may be hidden from view on mammography,” says Dr Teo.

Some women also have very dense breasts which make it difficult to detect small abnormalities. Because of these factors, a mammogram can detect about 90 per cent of breast cancer cases.

Women who require further testing may be sent for an ultrasound which is a medical imaging test that uses high speed sound waves to assess the tissues inside the body. The sound waves are converted into pictures which are then analysed by a technologist. Since it does not employ x-rays, an ultrasound is safe for pregnant women.

A breast ultrasound examination, in which a small hand-held probe is moved across the breasts, lasts for about 10-30 mi​nutes. It is useful for the following reasons:

• It evaluates the cause of breast symptoms such as a lump, swelling, breast pain.
• It determines if the lump is filled with fluid (a cyst) or is solid.
• It adds information to other tests such as a mammogram or a breast MRI.
• It helps guide the placement of needles for procedures such as a biopsy.

“If a breast lump is present, an ultrasound study may be able to accurately distinguish a benign lump from a cancerous one most of the time,” says Dr Teo. “Sometimes, in addition to the ultrasound, a biopsy may be needed to confirm that a lump is benign.”

Bottom line: While having its own advantages, a br​east ultrasound is not useful for detecting the microcalcifications seen in early breast cancer, says Dr Teo. It is best used for the evaluation of a breast lump or other breast symptoms.

Women aged 40 and above are advised to undergo a regular screening mammogram.​

Ref: S13​