The Relationship Between Hormones and Breast Cancer

When it comes to breast cancer, the role of hormones as a cause or treatment option is a highly discussed topic that medical experts continually debate. In fact, researchers have found a link between high levels of estrogen (the female sex hormone produced in the ovaries) and the development of breast cancer. Unfortunately, this means that certain treatments for menopause, namely hormone replacement therapy (HRT) that introduces both estrogen and progesterone into a woman’s system, may also put women at a greater risk of developing breast cancer.

Estrogen is the hormone that is responsible for triggering and regulating menstruation, as well as the growth of female sex organs, such as the breasts. In about 75 percent of all breast cancer cases, researchers have found that increased levels of estrogen in the blood promote the growth of abnormal cells in the breast. Doctors refer to these breast cancer patients as "estrogen receptor positive" (or ER+). Some women, especially postmenopausal women, fail or cease to respond to anti-estrogen treatments of hormone receptor positive breast cancer. When this occurs, other hormone treatments are available.

 

Along the same lines, the presence of progesterone (as well as progesterone receptors on the breast cells) has also been identified as a cause of breast cancer. Patients with abnormal cells disposed to progesterone are referred to as "progesterone receptor positive" (PR+).

 

Keep in mind, however, that not all cases of breast cancer are a result of presence of ER positive cells in a woman’s breasts. In fact, because roughly seven percent of the cases of breast cancer stem from purely genetic factors, researchers have attributed a number of environmental factors and lifestyle choices (such as diet, exercise and smoking practices) to the development of this condition.

Hormone replacement therapy (HRT) refers to the use of a set of hormones (namely estrogen and progesterone) in the treatment of menopause. Because menopause causes a woman to produce less estrogen, she can experience mood swings, hot flashes, a decreased sex drive and vaginal dryness. The theory behind hormone replacement therapy is that, by reintroducing estrogen to a menopausal woman’s body, these uncomfortable symptoms can be suppressed.

 

However, because increased levels of estrogen in the blood have been linked to the development of breast cancer, hormone replacement therapy is becoming more controversial. Typically, those who respond best to hormone therapy treatments are women who have both estrogen positive and progesterone positive receptors in their breast cells.

 

Consequently, it’s important to talk to your doctor before beginning a hormone replacement therapy in order to weigh the pros and cons. Make sure you understand the potential risks involved. If you are currently on an HRT regimen and your menopausal symptoms aren’t abating, consider ending this treatment, as exposing yourself to high levels of estrogen and/progesterone isn’t worth the risk of breast cancer if you aren’t alleviating the pain and discomfort associated with menopause.

 

Resources

What Role do Hormones Play in Breast Cancer Treatment? (2006) Retrieved June 29, 2007 From: http://www.breastcancer.org/tre_sys_hrt_role.html.

Gelmon, Karen (2007). Medical News from the Chair, “Hormones and Breast Cancer” (2007). Retrieved June 29, 2007 from: http://www.abreastinthewest.ca/news2.cfm?Num=41.