In breast cancer, one type of pathology includes cancerous cells that have hormone receptor on them.
These receptors are again of two types – estrogen receptors and progesterone receptors.
These hormone receptors are proteins on the breast cells that instruct the cells to grow indefinitely, causing cancer.
Breast cancer produced by estrogen receptors is called estrogen receptor positive (ER +).
Treatment of ER Positive Breast Cancer
Estrogen receptor positive breast cancer treatment consists of hormonal therapy. Here are the most commonly used methods for handling ER + breast cancer:
SERM (Selective Estrogen-Receptor Response Modulators) Treatment
Tamoxifen and Fareston are the two SERMs used to treat ER + breast cancer. They attach to the estrogen receptors on and in the breast cells and thus block the receptor sites. This way estrogen molecules cannot attach to these receptors.
They stop the estrogen production which means that there are not enough estrogen molecules in the body to attach to the receptors on the breast cells. Aromatase inhibitors work only in post menopausal women because they cannot impact the ovarian function of producing estrogen. In post menopausal women the main producers of estrogen are adipose tissue and adrenal glands. Drugs commonly administered under this category are: Anastrozole, Exemestane and Letrozole.
Estrogen-Receptor Downregualtors (ERD)
These are another class of drugs that work against estrogen structure and function. They work in 3 ways:
- Neutralize the action of estrogens
- Reduce the estrogen receptor numbers in the breast cells
- Alter the structure and configuration of the receptors so that the estrogen has no receptor to attach to
Some of the common estrogen receptor down regulators is fulvestrant. This drug is used to treat advanced stages of ER positive breast cancer in women that do not respond to other hormonal therapies like tamoxifen.
Luteinizing Hormone-Releasing Hormone Agents
This is another therapy that focuses on blocking estrogen production pathways in the ovaries. This is a short term solution to the problem as the drug has to be administered for many months with one injection per month. LHRHs are suitable modes of treatment for pre menopausal women who are in the early stages of the cancer. Zolodex, Lupron, Trelstar are the common drugs in this class. After stopping the treatment, the hormonal activity of the ovaries returns to normal. This recovery period varies from case to case.
The above mentioned categories of drugs are the first line of Estrogen receptor positive breast cancer treatment. If this fails then surgical removal of breasts and ovaries is the only solution.