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.
What you should know – types of breast cancer, their symptoms and receptor status
What are invasive breast cancers?
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)
Rarer forms of breast cancer
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
Diagnosis of breast cancer
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.
Your breast cancer can be characterised by the presence of ER, PR and/or HER2 receptors.
Understanding receptor status
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
Subtypes of breast cancer and how they are treated
While there are many different types of breast cancer, there are three main subtypes depending on your hormone and HER2 status.
HR positive HER2 negative breast cancer
This means there is no excess of the HER2 protein on the breast cancer cells, but they do have estrogen or progesterone hormones receptors. This is the most common type of breast cancer, and it is usually treated with hormone (or endocrine) therapy in the first instance.
HER2 positive breast cancer
Since HER2 is a protein receptor that promotes cell growth, HER2 positive breast cancers are generally faster growing than other types of breast cancer.
However, there are drug treatments called targeted therapies that can be used to treat HER2 positive breast cancer. The targeted therapy works by specifically targeting and blocking the HER2 protein, to slow or stop the growth of the cancer cells. It is usually used in combination with other treatments.
Triple negative breast cancer
If you have triple negative breast cancer, this means there are no oestrogen, progesterone or HER2 receptors on your breast cancer cells. This type of breast cancer does not respond to hormone treatment and is usually more aggressive and fast growing than other types. It is usually treated with chemotherapy.
Triple negative breast cancer is more commonly diagnosed in pre-menopausal women and has been linked to people who have a BRCA1 gene mutation.
Treatment for breast cancer
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.
- Health Promotion Board. (2018). Singapore Cancer Registry Annual Report 2018. Retrieved on 16 September 2021 from https://www.nrdo.gov.sg/docs/librariesprovider3/default-document-library/scr-annual-report-2018.pdf?sfvrsn=bcf56c25_0
- Breast Cancer. (2018). Signs and Symptoms of IDC. Retrieved on 16 September 2021 from https://www.breastcancer.org/symptoms/types/idc/symptoms
- Breast Cancer. (2019). Signs and Symptoms of IDC. Retrieved on 16 September 2021 from https://www.breastcancer.org/symptoms/types/ilc/symptoms
- Breast Cancer. (2012). Symptoms of Inflammatory Breast Cancer. Retrieved on 16 September 2021 from https://www.breastcancer.org/symptoms/types/inflammatory/symptoms