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Unopposed Estrogen therapy, Menopause, and the Risk of Invasive Breast Cancer

Review on November 12, 2009

Menopause invasive cancer

Despite evidence suggesting that short-term unopposed estrogen therapy use does not raise the risk of breast cancer, the effects of longer-term use remain unclear. All of the women in this study have gone through menopause and factors such as their age at menopause are taken into account when assessing a possible link between unopposed estrogen therapy, menopause, and the risk of invasive breast cancer. This investigation focuses on the length of estrogen therapy use and the risk of invasive breast cancer over an extended follow-up period in women who have undergone menopause.

In 1990, breast cancer risk factors among female participants in this survey, all of whom had been through menopause, differed in terms of use and duration of estrogen therapy. In a various categories, such as age and age at menopause, women who had never used estrogen therapy were similar to women who had used estrogen therapy for over a decade, but varied from those who currently used estrogen therapy for less than 10 years.

It was discovered that females who had gone through menopause and had never tried estrogen therapy were less likely to have history of benign breast disease or to have undergone screening within the previous 2 years, and more likely to have a family history of breast cancer. Women who had gone through menopause and who had used estrogen therapy for more than 10 years were more slender and more likely to have had a bilateral salphingo-oophorectomy, which is commonly thought to lower the risk of breast cancer.

Menopause incision

As expected, for women who had gone through menopause and had used estrogen therapy for 20 years or more, the correlation seemed greater for estrogen receptor (ER) or progesterone receptor (PR) cancers.

Existing estrogen therapy users at this time were also more likely to have had a bilateral salpingo-oophorectomy and to have entered menopause at an earlier age, and thus may have reduced their risk of breast cancer compared with women who had undergone menopause but never used estrogen therapy.

Among women who used estrogen therapy for less than 20 years, no significant increased risk of breast cancer was observed on the whole. Though, there was a greater risk with longer durations of use, primarily for ER+/PR+ cancers.

This investigation shows that in terms of age and age at menopause, women who had never tried estrogen therapy differed from those who currently used estrogen therapy for less than 10 years. It was also found that current estrogen therapy users were more likely to have had a bilateral salpingo-oophorectomy and to have started menopause at an earlier age, and therefore may have reduced their risk of breast cancer compared with women who had undergone menopause but never used estrogen therapy. Thus, it seems age at menopause can play a part in the risk of invasive breast cancer. Although existing use of estrogen therapy for less than 10 years was not associated with a statistically considerable increase in breast cancer risk, the WHI showed an increased possibility of stroke and deep-vein thrombosis in the same time frame. Therefore, women who use estrogen therapy to prevent or treat osteoporosis will do so for longer and are recommended to look into alternative options in light of the fact that longer-term use of estrogen therapy can increase the risk of breast cancer.