Breast cancer is the most common cancer among women in Singapore and the number of cases is about 1100 per year. The lifetime risk for a Singapore woman to develop breast cancer is now approximately 1 woman in 16 to 18 women. Therefore, breast cancer is a very important problem in our local context and should be actively screened for and treated.

There are 2 types of breast cancer screening. Opportunistic type whereby the patient presents herself to the clinic for mammogram and breast examination. There is also the mass screening or population based screening, where asymptomatic women in a population who are eligible, are called or invited for a screening programme.

What is the aim of screening for breast cancer?

It is to detect in-situ as well as invasive breast cancer. It is hoped that with earlier detection we will be able to shift the incidence of breast cancer to the pre-invasive type and thereby decrease the mortality associated with breast cancer. At the same time, breast cancers that are detected through screening are usually smaller, at an earlier stage and after the patient undergoes treatment, have a better prognosis. The overall benefit from breast cancer screening for all eligible ages of women is a reduction is cancer mortality of about 20-40% according to different studies.

Women have to be constantly reassured that more that 90% of asymptomatic women who go for screening are actually found to be normal and do not have cancer. The goal for screening is to exclude cancer and determine that they are well. They therefore should not be hesitant to undergo screening. Screening mammograms are performed by doing a 2 view x rays of each breast. This is complemented by ultrasound examination of the breasts and also clinical breast examination, which is conducted by a doctor. All ladies are encouraged to perform breast self examination on a monthly basis to detect any new abnormality or lumps in the breast.

At the National Cancer Centre, we are fortunate to be equipped for conducting good breast cancer screening. The mammography suite is a well staffed with experienced radiographers to perform the necessary mammograms and ultrasound, and they are supported by a group of trained specialist radiologists and surgeons who have a special interest in breast cancer detection, diagnosis and treatment.

If any abnormality is detected at the time of screening, a lady would then proceed on to a diagnostic biopsy to determine the nature of the suspicious lesion. This diagnostic biopsy may take the form of a minimally invasive i.e. the use of a core biopsy needle or mammotome, or open surgical biopsy, depending on the type and location of the suspected lesion and also the patient’s wishes. If unfortunately, the diagnosis of breast cancer is made, definitive treatment would be recommended.

Who is eligible and should go for breast cancer screening?

All asymptomatic women of 40 years and above should go for regular mammographic screening. For ladies between the ages of 40 to 49, they should go for a yearly mammogram. Those from 50 to 70 years of age should go for 2 yearly mammograms. Women with a family history of breast and/or ovarian cancer, known carriers of the BRCA1/2 gene or those with prior biopsy with high-risk pathology should undergo screening earlier even before the age of 40 years. They may also need to be evaluated at a cancer risk assessment clinic.

There are usually no contraindications for doing a mammogram. Even patients with breast implants can and should go for regular mammographic screening. Nevertheless, one group of patients who may encounter difficulty is those with free silicon injections into the breast parenchyma. This results in multiple irregular densities on the mammogram, rendering mammograms ineffective as a screening tool. These women would need to assessed by regular clinical examination and may even need an MRI of the breast should any suspicious lesions be detected.

It is very important to create awareness among our local population about breast cancer screening and to reassure them that the majority coming forward would be deemed normal and found to have no abnormalities in the breast. If an abnormality is detected, early diagnostic biopsy can be performed at the National Cancer Centre. Even if cancer is diagnosed, early detection usually means a smaller cancer and with prompt definitive treatment, more breasts and ultimately more lives can be saved.

Yong Wei Sean
Consultant
Surgical Oncology
National Cancer Centre, Singapore