Getting a breast cancer diagnosis can be scary, and it can be difficult to understand the amount of information available. However, one of the most important pieces of information is the type of breast cancer. Understanding the type of breast cancer helps determine which treatments are most effective and the likelihood of recovery.
HOW ARE TYPES DEFINED?
The type of breast cancer is defined by the tumor’s genetic profile. “Cancer” refers to cells multiplying at a rate much higher than normal cells, and this is because there is a mutation, or something has gone wrong, in the tumor cells’ DNA. The type of mutation defines the type of tumor.
HR + /HR- : “HR” refers to hormone receptors. If a tumor is “HR positive (HR+),” it means the tumor has is frequently treated with hormone therapy, or anti-estrogen therapy. This is different from hormone replacement therapy (targeted primarily to post-menopausal women). Hormone therapy for breast cancer attacks the hormone receptors of the tumor, attempting to kill them or keep them from multiplying. If a tumor is HR-, it is unlikely that hormone therapy will be helpful, and it is not usually administered.
The two types of hormone receptors are estrogen and progesterone. Either one can be expressed, and different types of treatment apply to each category. However, the delivery and maintenance of therapy is similar.
HER2 stands for Human Epidermal growth factor Receptor 2. It is one of the receptors that tends to cause faster growth and aggressive metastases (quick spread) of the disease. HER2 positive (HER2+) tumors are found in approximately 25% of patients, but the prognosis for many of these patients is very good. A chemotherapeutic drug (Herceptin) is available that has shown tremendous rates of success against tumors expressing HER2.
TRIPLE NEGATIVE TUMORS
Triple negative tumors do not express estrogen or progesterone (ER or PR), or HER2. They also tend to be the most aggressive, malignant tumors. Unfortunately, while there are treatments available, because hormone therapy is not useful and the HER2 treatments are unlikely to work, more experimental treatments are usually engaged for triple negative breast tumors. However, because of the danger they present (and their presence in roughly 10% of breast cancer patients), scientists and pharmaceutical/biotech companies are working hard to find effective treatments for triple negative patients.
Due to the amount of knowledge we have gathered about breast cancer, treatments and outcomes have greatly improved over the years. However, that same information can make things confusing for patients and families. For any of these types of tumor or any other questions, contact your doctor or an oncologist for more information.
Source: Mayo Clinic. http://www.mayoclinic.com/health/breast-cancer/HQ00348. Accessed 27 December 2009.
Breastcancer.org. http://www.breastcancer.org/treatment/hormonal/. Accessed 28 December 2009.
“Understanding and Treating Triple Negative Breast Cancer.” http://www.medicalnewstoday.com/articles/134622.php. Accessed 28 December 2009.