Medically Reviewed by Dr. K on 26 March 2021
Types of Breast Cancer
Hormone Receptor-Positive Breast Cancer
ER-positive breast cancer accounts for almost 80% of all breast cancers. That means that cancer cells respond to oestrogen by growing. About 65% of these are also “PR-positive.” Another hormone, progesterone, causes them to develop.
It's called hormone-receptor-positive if your breast cancer has a large amount of oestrogen or progesterone receptors.
ER/PR-positive tumours are significantly more likely to respond to hormone therapy than ER/PR-negative tumours.
Once the surgery, chemotherapy, and radiation therapies are completed, you will be eligible for hormone therapy. By suppressing the influence of oestrogen, these medications may help prevent the cancer from recurring. They do this in a variety of ways.
- Tamoxifen (Nolvadex) acts by blocking hormone receptors and preventing hormones from binding to them, which helps to prevent cancer from returning. It can be used for up to 5 years following initial breast cancer treatment.
- Aromatase inhibitors are a form of medication that inhibits the synthesis of oestrogen. Anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara) are some of them. They are only recommended to people who have already completed menopause. Fulvestrant (Faslodex) is an oestrogen-blocking and oestrogen-damaging drug that is often used to treat metastatic breast cancer. Toremifene (Fareston) is an oestrogen receptor antagonist that may be used to treat certain patients with metastatic breast cancer.
- Abemaciclib (Verzenio), palbociclib (Ibrance), and ribociclib (Kisqali) are CDK 4/6 antagonists that are often combined with aromatase inhibitors or the hormone therapy fulvestrant (Faslodex).
HER2-Positive Breast Cancer
The cells of around 20% of breast cancers produce so much of a protein called HER2. These cancers are usually aggressive and rapidly spread.
The targeted medication trastuzumab (Herceptin) has been shown to significantly minimise the likelihood of the cancer returning in women with HER2-positive breast cancers. This drug is given to women with breast cancer that has spread to other places following surgery, along with chemotherapy. It may also be used to treat breast cancer in the early stages. However, there is a small but possible chance of heart and lung injury.
Other selective drugs are occasionally used in the treatment of HER2-positive breast cancer. There are some of them:
- Ado-trastuzumab emtansine (Kadcyla)
- Fam-trastuzumab deruxtecan-nxki (Enhertu)
- Lapatinib (Tykerb)
- Margetuximab (Margenza)
- Neratinib (Nerlynx)
- Pertuzumab (Perjeta)
- Tucatinib (Tukysa)
Triple-Negative Breast Cancer
Certain breast cancers (between 10% and 20%) are referred to as “triple-negative.", as they suppress oestrogen and progesterone receptors and do not overexpress the HER2 protein, Many of the breast cancers linked to the BRCA1 gene are triple-negative. Surgery, chemotherapy, and radiation are often used to treat them.
- Olaparib (Lynparza) and talazoparib (Talzenna) are targeted therapy drugs that can be used to treat patients with metastatic HER2-negative breast cancer that have a BRCA mutation. These medications work by inhibiting a protein known as PARP.
- Atezolizumab (Tecentriq) is an immunotherapy medication that is used in conjunction with the chemotherapy nab-paclitaxel (Abraxane) to block the protein PD-L1 in triple-negative breast cancers.