A mammogram is a low-dose X-ray of the breasts that detects abnormalities that may represent ductal carcinoma in situ (DCIS), or breast cancer.

DCIS is a non-invasive cancer that presents as an u​ncontrolled growth of cells within the breast ducts. It is referred to as stage 0 of breast cancer and the majority of women diagnosed with DCIS are cured. Cancer of the breast tissue is invasive breast cancer. Breast cancer is the most common cancer among women in Singapore.

For women who are between 40 and 49 years of age, a mammogram is recommended every year. For those 50 years old and above, it is recommended once every two years.

A question frequently asked by women undergoing a routine mammogram is: “What if an abnormality is found? What does it mean and what do I do next?” The patient may require additional imaging tests such as a diagnostic mam​​mogram and an ultrasound, and may need a biopsy to determine the nature of the abnormality.

“It can be unsettling for any woman to be told that her mammogram results are abnormal. But this does not mean she has a tumour or that she has cancer,” explains Dr Yong ​Wei Sean​, Senior Consultant, Department of Surgical Oncology, National Cancer Centre Singapore (NCCS), a member of the SingHealth group.

According to BreastScreen Singapore (BSS) in Singapore, for every 1,000 women screened, about 100 are called back for assessment. Of these, about 30 would need to undergo a breast biopsy, and about 5 to 8 would have breast cancer.

Therefore, if an abnormality has been found in your mammogram, it is important to follow up with further tests.

The follow-up appointment: Assessing abnormality in your mammogram

At your follow-up appointment, it is likely that you may need to go through the following:

  • Diagnostic mammogram: This is a more detailed mammogram that may take longer than the usual 15 to 20 minutes required for your screening mammogram. Dr Yong adds: “The X-ray technician will take a few more X-rays of your breast, especially if the previous images from your screening mammogram were not clear enough.” – that is,​ additional magnification or cone compression views may need to be taken of those areas in the breast that are of particular concern.
  • Ultrasound: During this process, the technician will apply a cool, clear gel to your breast before placing a microphone-shaped device known as a transducer on it. The transducer releases high-frequency sound waves and picks up the echoes, creating an image of the breast tissues on a computer. An ultrasound is useful to further study an area of abnormality in the breast.
  • Magnetic resonance imaging (MRI) test: If the abnormality can’t be confirmed by the ultrasound, you may need an MRI test. In this case, magnets and radio waves are used to create detailed pictures of the internal breast. This test is done in very select cases, where the patient has specific indications.

Find out when a breast biopsy is required in the next page.

​Ref: S13