Estrogen receptor-positive (ER+) breast cancer is the most
common type of breast cancer diagnosed today. According to the American
Cancer Society, about two out of every three cases of breast cancer are
hormone receptor positive. Most of these cases are ER+ or receptive to both
estrogen and progesterone.
If your doctor suspects breast cancer, you will likely have a biopsy done. A pathologist will test your cells to see if they are cancerous. If they find cancer, they’ll also test the cells for various characteristics including what receptors are present on the surface of the cancer cells. The outcome of this testing is important when making treatment decisions. What treatment options are available is highly dependent upon the results of these tests.
If you have ER+ breast cancer, your cancer cells grow in the presence of the hormone estrogen. Estrogen is a naturally occurring substance in the body. By blocking estrogen, doctors can improve the likelihood of controlling ER+ breast cancers. ER+ breast cancers have the most favorable prognosis of all subtypes, according to a study in Surgery, Gynecology & Obstetrics. ER+ cancer type typically responds to hormone therapy. Even with a relapse, this type is easier to manage than ER- tumors. Further, some of the observed declines in women’s breast cancer mortality rates can be attributed to the effectiveness of hormone therapy drugs prescribed for ER+ women.
Your prognosis depends on the stage at which your cancer was discovered. Cancer is staged numerically. Each number reflects a number of different characteristics of your breast cancer. These include the size of the tumor, the differentiation of the cells, and whether cancer has moved into lymph nodes or surrounding tissues. Importantly, the cancer subtype doesn’t play a role in staging, only in treatment decisions.
Overall survival statistics of women with the major subtypes of breast cancer — such as ER+, HER2+, and triple negative — are combined together. However, with treatment, the vast majority of women with very early stage breast cancers can expect to live a normal lifespan.
Survival rates are based on how many people are still alive years after they were first diagnosed. Five-year survival rates are commonly reported, as are ten-year survival rates.
According to the American Cancer Society, five-year survival rates are:
- stage 0: 100 percent
- stage 1: 100 percent
- stage 2: 93 percent
- stage 3: 72 percent
- stage 4 (the metastatic stage): 22 percent
One thing to note is that these statistics also included women with the more aggressive HER2+ subtypes as well as triple negative cancers. Additionally, it takes five years to get to a five-year statistical survival rate, so newer therapies are not included in these numbers. It’s likely that an ER+ woman diagnosed with breast cancer today may actually have a significantly higher overall survival.
All women who have ER+ cancer will be recommended an estrogen-blocking drug. In some cases, they may also have their ovaries removed. Pre-menopausal women will likely use the drug tamoxifen. Post-menopausal women may use an aromatase inhibitor. While both act in different ways, both treatments starve the cancer of an important factor that it needs in order to grow.
Other treatment options vary by stage. In cases where the tumor is small and hasn’t spread to the lymph nodes, lumpectomy may be possible. A lumpectomy removes breast tissue but not the entire breast. Your doctor may recommend radiation along with a lumpectomy, but chemotherapy may not be necessary.
In cases of early stage cancer, you can ask your doctor if an Oncotype DX test is appropriate. This test will examine genes within the cancerous tumors. It can help identify whether your risk of relapse is high. The test can also show whether chemotherapy is a good option or not. The Oncotype DX, which may be paid for by Medicare and most insurance plans, is recommended for women who:
- have a stage 1 or 2 tumor
- have cancer that has not spread to the lymph nodes
- are ER+
If your cancer is discovered at stage 3, you may have to have more extensive treatment. Stage 3 involves a larger tumor or cells found in the lymph nodes or chest wall. In this stage, breast removal, also called a mastectomy, may be required. In this case, you may also need a course of chemotherapy. In some cases, women undergoing this surgery may do chemotherapy before surgery. This is called neoadjuvant chemotherapy.
Advanced cancer, or stage 4 cancer, means that the tumor has already metastasized and taken up residence in another organ. This usually occurs in the bones, liver, lungs, or brain. Stage 4 is the end stage of breast cancer. However, it’s fortunately uncommon to discover advanced cancer upon initial diagnosis. At this stage of disease, cancer subtypes are less important than whether a patient responds to a specific treatment. Even with advanced ER+ cancer, it is considered a manageable disease. Although at this point the cancer is incurable, a woman with stage 4 ER+ may respond well to hormonal therapies, extending life for many years.
Estrogen receptor-positive breast cancer is treatable and manageable, especially when it’s discovered early. Latter stages have a worse prognosis, but fortunately, later stages are less common at the time of diagnosis and can still be treated.
While discovering any kind of cancer is frightening, treatments for ER+ cancer are tried and proven to work. The odds for a long life are excellent.