Once you've been diagnosed with breast cancer, there can be a lot of new medical terminology to deal with. Along with learning about the stage of the cancer, patients may hear terms such as hormone receptor-positive, HER2-positive, or triple-negative breast cancer. These terms are for the type of breast cancer. There are many types of breast cancer. Subtypes can have varying growth rates, sensitivity to therapy, and prognosis. Knowing the subtype will help a doctor determine the best treatment for every patient.
What are the subtypes of breast cancer?
The different types of breast cancer are determined based on the presence or absence of certain proteins in cancer cells. These proteins may be used by doctors to determine what is causing the cancer to grow.
The 3 major markers tested are:
Estrogen receptor (ER)
Progesterone receptor (PR)
Epidermal growth factor receptor 2 (EGFR2)
These markers help to determine the subtype of breast cancer. Breast cancer that tests positive for one or more of the hormones estrogen and/or progesterone.
The most prevalent type of breast cancer is hormone receptor-positive. In this type, cancer cells contain receptors for estrogen and/or progesterone. These hormones may promote the development of cancer. This is why hormone-blocking or hormone-reducing drugs can be effective. Hormone receptor-positive breast cancers grow more slowly than other types and can be treated with hormone therapy.
HER2-Positive breast cancer
Breast cancer that has HER2 is rich in the HER2 protein. A protein involved in regulating cell growth. In the presence of an excess amount of HER2, cancer cells grow and divide faster.
Specific therapy has been developed for HER2-positive breast cancer and has greatly enhanced the prognosis of this cancer. These drugs inhibit the HER2 protein and help halt cancer growth.
Triple-Negative breast cancer
Triple-negative breast cancer lacks extra HER2 protein, as well as estrogen and progesterone receptors. Hormone therapy and HER2-targeted treatment do not work for this subtype, as the common targets are not present.
The treatment typically includes surgery, chemotherapy, and radiation therapy, as well as, in some instances, immunotherapy. Triple-negative breast cancer is a more aggressive type of breast cancer than some other types.
A Doctor's Guide to the Subtype Identification
Subtype is determined by laboratory tests of tissue obtained at biopsy or surgery. The tumour is examined by a pathologist, and the tumour type is also examined for ER, PR status, and HER2. The findings aid the doctors in understanding the biology of the cancer and determining which treatment is likely to be most effective.
These tests are regularly and importantly used for breast cancer diagnosis.
The importance of the Subtype
Information about the subtype enables the doctor to tailor the treatment. For example:
Hormone therapy might be effective for hormone receptor-positive cancers.
Targeted HER2 drugs may be effective in treating HER2-positive cancers.
Triple-negative cancers may need a different treatment strategy.
The subtype can also give information on the way the cancer can behave and the treatment that may be of the most benefit.
Understanding Your Results
At first, a pathology report may seem daunting. ER-positive, PR-positive, or HER2-positive may sound like jargon, but it provides important information about the cancer. Understanding your subtype can help you better understand treatment suggestions and talk with your health care team. The diagnosis itself may sound complicated, but it is an essential component of a person's cancer diagnosis and becomes the first step in creating a treatment plan for a person's type of cancer.