Combined hormonal therapy linked with increased breast cancer
According to a study published in the Journal of the National Cancer Institute, hormone therapy with estrogen and progestin is correlated with an increased incidence of breast cancer and mortality. Breast cancer is the most common form of cancer in women and it is estimated that one in eight women will develop at some time in their lives breast cancer. There are many risk factors for breast cancer such as age, family history, medical history. These are risk factors that cannot be controlled but there are risk factors that can be controlled such as weight, alcohol consumption, diet (red meat, processed foods, fats, etc.), smoking, physical inactivity, oral contraceptives, stress, etc. . Recently researchers conducted a study that found that combined hormone therapy (estrogen and progestin) increases breast cancer risk and mortality. However most observational studies to date have not demonstrated this connection.
To clarify this issue, Rowan T. Chlebowski, MD, PhD, Los Angeles Biomedical Research Institute (LA BioMed) researcher along with his team, have investigated postmenopausal women without hysterectomy who received or not estrogen and progestin combined therapy. The conclusion was that the incidence of breast cancer among women who used combined hormone therapy (estrogen plus progestin) have been higher compared to those who had never used combined hormone therapy. Also, it seems that the incidence of mortality was higher among those women who used estrogen plus progestin therapy. In addition it was found that women who started hormone therapy closer to menopause have a higher risk of breast cancer. Moreover, it appears that the incidence is increased for all categories of breast cancer, not just for those with favorable prognosis.
The authors said that: “Because survival after breast cancer diagnosis did not differ between estrogen plus progestin users and nonusers, the higher breast cancer incidence of those using estrogen plus progestin may lead to increased breast cancer mortality on a population basis.”
It is known that exposure to estrogen for a long time, uninterrupted, may increase the risk of breast cancer. Estrogens are hormones that cause cell proliferation in the mammary gland, and it seems that women with early menarche (starting menstruation before age 12 years) or those with late menopause (over age 55) have a higher risk of breast cancer. Also, there is an increased risk for women exposed long time to estrogens in the environment such as DDT or pesticides in food. It should be noted that approximately 10% of breast cancers are due to genetic mutations (the most common are BRCA1 and BRCA2 mutations). Women with these mutations have a 80% risk to develop breast cancer.