Breast cancer continues to be a common disease in Singapore, ranking as the number one cancer affecting women¹. However, breast cancer cannot be encompassed into one type alone. In fact, there are a variety of breast cancers – some common and others very rare.

Breast cancer generally develops in the breasts’ milk ducts or lobules. When a breast cancer is invasive, the abnormal cancer cells spread beyond these areas to attack other healthy breast tissue.

There are two main types of invasive breast cancer in Singapore. These are invasive ductal carcinoma (IDC) and invasive lobule carcinoma (ILC).

Invasive ductal carcinoma (IDC)

Starting in the milk duct, invasive ductal carcinoma (IDC) has broken through the milk duct’s lining and spread into the breasts’ surrounding tissue. These ducts are the tubes that carry milk to the nipple. Once the cancer has started to spread, this provides an opportunity for the cancer to enter the body’s lymph nodes and metastasise outside of the breast area.

Invasive lobule carcinoma (ILC)

Invasive lobule carcinoma (ILC) originates in the breast’s lobules before spreading to nearby tissue. It is these lobules that produce breast milk. Once ILC has begun to spread it can then move to other areas of the body, becoming an advanced form of cancer.

Symptoms for IDC and ILC

Both IDC and ILC may develop without any signs or symptoms² which is why regular breast screenings are so important. ILC can also be harder to detect in mammograms, as it often forms in a line formation rather than a lump. Potential signs and symptoms include³:

• Breast thickening (usually present for ILC)
• Swelling in the breast
• Pain in an area of the breast and/or nipple
• Nipple discharge that is not milk
• Changes in breast skin or nipples (dimpling, redness, irritation, scaliness or thickening)

Some breast cancers are less common, but you should still be aware of their signs and symptoms when performing a breast self-examination. One of the primary rare cancers in Singapore is inflammatory breast cancer.

Inflammatory breast cancer

Inflammatory breast cancer has different signs and symptoms compared to IDC and ILC. Rather than developing as a mass, inflammatory breast cancer affects the blood vessels and causes inflammation in the breast.

A mammogram is unlikely to show inflammatory breast cancer, which can be advanced upon diagnosis. Some signs and symptoms of inflammatory breast cancer include⁴:

• Redness of the breast
• Breast warmth or a burning sensation
• Orange-peel appearance
• Swelling of the breast and lymph nodes

Alongside tests and scans used to diagnose breast cancer, such as a mammogram and ultrasound, breast cancer cells will be extracted during biopsy to identify the receptor status of your cancer.

The hormone receptor status you receive may include:

• ER+ (or ER positive) breast cancer – has receptors for oestrogen. They respond and grow in the presence of oestrogen
• PR+ (or PR positive) breast cancer – has receptors for progesterone. They respond and grow in the presence of progesterone
• HER2 positive breast cancer – has a higher than normal amount of HER2 protein receptors on the surface of the breast cells

The treatment you receive for breast cancer will depend on the type of cancer you are diagnosed with and if it has spread. It is important to speak with your care team to understand which option is best for you. To learn more about treatments for breast cancer, click here.