Breast Cancer Screening

What is screening?

Screening is the process of looking for a disease that has yet to exhibit any overt signs (eg. a lump) or symptoms (eg. pain). A number of diseases progress over a period of months or years, and in the early stages of progression, are too small to cause any symptoms or signs. Some diseases, like cancer, start to metastasize, or spread, to other organs as they progress. Treatment at this advanced stage is difficult, with low cure rates. Detecting these diseases at early stages frequently affords the best chance of cure.

What is breast cancer?

Breast cancer develops in the breast tissue of both women and men. It is far more common in women. Singaporean women have a lifetime risk of about 1 in 17 of developing breast cancer. It is the commonest cancer in women here. The cancer starts out when abnormal cells divide uncontrollably. This is initially undetectable. Given some time, the collection of abnormal cells enlarges, and though not large enough to be felt or seen, may be detected on mammograms or ultrasound scans. If more time passes, the collection of cells may be detected by physical examination. Somewhere along this growth period, some cells may break away from the main collection and travel in lymphatic channels to lymph nodes that usually lie in the armpit area. These breakaway cells start dividing here. Cells can then travel in the blood stream to distant organs such as the liver, bones and lungs.

Advantages of screening?

• Detection of cancer at earlier stages means the chance of cure and of livinglonger are much improved.
• Detection of cancer at earlier stages frequently means a smaller, less disfiguring operation can be performed to remove the tumour.
• Earlier detection may reduce the need for chemotherapy after surgery.

Disadvantages of screening?

No test is 100% accurate; this means a small number of women with normal breasts may have to undergo additional testing and biopsy before they can be safely regarded as having no cancer.

Unfortunately, the reverse is also true; very early cancer may rarely be missed by the screening tests. These women may be falsely reassured.

Who to screen?

• All women should be breast aware. This means being aware of the normal shape and appearance of their breasts. Periodic breast self-examination may facilitate breast awareness.
• Women in the 40-49 years age group should have annual breast screening.
• Women 50 years old and above should have screening every two years.

How to Screen?

The usual screening method used is an Xray called a mammogram. In this simple procedure, Xrays are taken of each breast. These images are then reviewed by a radiologist. The findings are categorized according to the likelihood of there being cancer. Patients with a very low likelihood of having cancer do not require any further investigation. Some patients may be found to have breast lumps that appear benign (ie non-cancerous). Some of these can be safely observed for a period of time, and some of these need to be biopsied (ie some cells removed from the lesion and examined under a microscope). Your doctor will decide on the better option for you.

Most lumps found on screening turn out to be benign.

Another screening test used is an ultrasound scan. This procedure is generally better for patients with dense breasts. It is also frequently used in addition to the mammogram.

WARNING SIGNS

• A lump in the breast, especially if it increases in size over time.
• A persistent rash around the nipple.
• Bleeding or discharge from the nipple.
• An inverted nipple, if of recent onset.