What is Breast Cancer?
Breast cancer is a cancer of the breast tissue. It arises from the uncontrollable cell growth of cells in the breast.
Are All Breast Lumps Cancerous?
- 80% of breast lumps are benign and could be:
- Breast cysts
- 20% are cancerous
Are You at Risk?
- Significant Risk
- Family history of breast cancer and ovarian cancer
- Carrier of BRCA genes
- Ovarian cancer patients
- Patients with previous history of breast cancer
- Presence of breast lumps – atypical hyperplasia, carcinoma in situ
- Moderate Risk
- Single, late childbirth, no children
- Not breastfeeding
- Use of oral contraceptive pills
- Use of hormonal replacement therapy
- General Risk
- Affluent diet that is rich in fat, cholesterol, carbohydrates and red meat
- Obesity, sedentary lifestyle
- Alcohol and cigarette consumption
What Are the Symptoms of Breast Cancer?
- Breast lump
- Skin dimpling
- Change in skin colour or texture
- Change in how the nipple looks, for example nipple inversion
- Clear or bloody fluid leaking out of the nipple
How Is Breast Cancer Diagnosed?
- Blood test
- Biopsy tissues
- Imaging tests:
- CT scan
- Bone scan
- PET-CT scan
How Does Mammography Screen for Breast Cancer?
- Mammogram can detect early breast lesions that are less than 1 cm in size
- Higher possibility of being able to have breast-conserving surgery
- Can minimise the need for chemotherapy
- Survival rate is generally better
What Is the Treatment for Breast Cancer?
- Breast surgery
- Hormonal therapy
- Targeted therapy
Triple-negative Breast Cancer
Triple-negative breast cancer (TNBC) is a type of cancer that lacks the expression of three breast cancer cell receptors and cannot receive hormonal or targeted therapy. Traditional chemotherapy doesn’t have significant effects on TNBC, hence it has been regarded as a difficult breast cancer to treat. Nowadays, we can can combine immunotherapy with chemotherapy, allowing chemotherapy to polish off the surface of the tumor, remove its immune-protective layer and expose it, thereby assisting immune cells to recognize cancer cells and launch targeted attacks.
For a long time, breast cancer has been clinically staged based on tumour size (T), lymph node status (N), and metastasis (M), to predict patient prognosis and treatment plan. In the past 20 years, we have also included the biological characteristics of tumour cells in our medical evaluation to select targeted therapies. Breast cancer is divided into different molecular subtypes according to the biological characteristics of tumour cells, including Estrogen Receptor (ER), Progesterone Receptor (PR) and Human Epidermal Growth Factor Receptor Type II (HER-2).
TNBC is a type of breast cancer that is negative for the above three receptors. It accounts for about 10% of all breast cancer types in the world. The other 70% are hormone receptor-positive breast cancers and 20% are HER-2 positive breast cancers.
Both ER and PR are hormone receptors. If they are positive in a breast cancer, hormone therapy can block their effects on tumour cells. HER-2 is an oncogene. There are currently HER-2-targeted treatments that can inhibit tumour cell growth and control the disease. In contrast, TNBC lacks the expression of three breast cancer cell receptors and cannot receive hormonal or targeted therapy. It is regarded as the most difficult type of breast cancer to treat. In TNBC, cancer cells also metastasize more easily to other organs.
Who are at Risk for TNBC?
TNBC afflict mostly afflict women who are relatively young. Women with TNBC on average survive up to 15 months. 17% of breast cancer patients in Malaysia have TNBC. Most of them are relatively young (less than 50 years old). Those with TNBC are often women in their 30s or 40s, but their lifespan is short due to their complicated medical condition. The 5-year survival rate of patients with other types of breast cancer is up to 93%, while that of TNBC is only about 77%.
On the other hand, carriers of the breast cancer genes 1 and 2 (BRCA 1 and BRCA 2) mutation are also more likely to develop TNBC. BRCA is a gene related to hereditary breast cancer. About 70% of patients with mutated BRCA genes have TNBC.
Treatment for TNBC
For a long time, patients with metastatic TNBC can only receive traditional chemotherapy. However, the effect is not significant. The longest survival period is 12 to 15 months. There had been no breakthrough for a long time, until the emergence of immunotherapeutic drugs, which brought new hope to these patients.The combination of immunotherapy and chemotherapy can extend the overall survival of patients with triple-negative metastatic breast cancer, while reducing the risk of cancer progression.
Currently, immunotherapy needs to be combined with chemotherapy. Chemotherapy first polishes the surface of the tumour, removes its immune protective layer and exposes it, thereby assisting the body's immune cells to recognize cancer cells in order to identify and "attack" them. However, immunotherapy is not suitable for all triple-negative breast cancer patients. They need to meet one condition: their tumour cells need to contain more than 1% PD-L1 ligand for immunotherapy to be effective. PD-L1 is a protein that is present on the surface of cells that allows the human immune system to recognize the cell as normal instead of foreign.
When the T cells of the human immune system discover a 'foreign' object, they launch an attack. However, the tumour cells produce PD-L1 on their surface and can bind to the PD-1 receptor of the T cell, causing the T cell to mistake it for a normal cell. Hence, the T cell does not send out an attack signal, and the tumour escapes the attack.
Tumour cells cleverly hide themselves in the human body. Therefore, the mode of action of traditional chemotherapy is to kill all cells regardless of whether the cells are good or bad, whereas the immunotherapy drug atezolizumab specifically binds to PD-L1, inhibiting its interaction with PD-1. The drug activates the patient’s own immune system to recognize and attack tumour cells.
Immunotherapy has less side effects than targeted therapy and chemotherapy. We still need to combine immunotherapy with chemotherapy, so patients may still experience common side effects of chemotherapy, such as hair loss, nausea, loss of appetite, and fatigue. The side effects of immunotherapy are usually weaker than those of targeted therapy and chemotherapy, but immunology is rather complicated.
Every person’s immune response is different. Immunotherapy may still cause some side effects, namely immune-related inflammation, such as fever, asthma, and cough, or pneumonia, etc. This is because in the process of stimulating the immune system to recognize tumour cells, the immune response will become more active, and will sometimes attack healthy cells if it is not controlled.
Currently, immunotherapy is administered by intravenous injection. Patients do not need to be hospitalized, but the number of visits to the hospital will be more frequent. Although immunotherapy still does not cure cancer, it can prolong the survival rate. Therefore, patients with triple-negative breast cancer should not be disappointed. As long as there is a glimmer of hope, they should actively cooperate with treatment, and at the same time look forward to more effective therapies or drugs in the future.
The symptoms of triple-negative breast cancer are no different from other types of breast cancer. Common symptoms include breast or nipple pain or depression, breast lumps, nipple discharge, and changes in breast shape. Women, especially those with family history and those belonging in the high-risk groups, are encouraged to take the initiative to undergo mammography or ultrasound.
All types of cancer, including triple-negative breast cancer, should be detected and treated as soon as possible. Women should perform self-breast examinations regularly and seek medical advice if they find something unusual. Even if triple-negative breast cancer is diagnosed, the effect of an early treatment will be better than the late or terminal stage.