The role of hormone replacement therapy and the risk of development of ovarian cancer

Hormone replacement therapy (HRT), which is mainly used to relieve climacteric symptoms, increases a woman’s risk for breast cancer, uterine endometrial cancer, but the association with ovarian cancer is less clear. Based upon epidemiological research there is evidence that steroids hormones, primarily estrogens and progesterone have an impact on ovarian carcinogenesis. The latest data have indicated that estrogens favour neoplastic transformation within the ovarian surface epithelium. There has been demonstrated a differential expression of ER alpha or beta during ovarian carcinogenesis, with an overexpression of ER alpha as compared with ER beta in cancer. The loss of ER-beta expression may be an important event leading to the development of ovarian cancer. ER- beta is a regulator of proliferation and motility of ovarian cancer cells. On the other hand, high progesterone levels offer a protection against development of ovarian carcinoma and overexpression progesterone receptors, which in turn, is associated with favourable prognosis in patients with ovarian cancer. Recent prospective epidemiological studies have indicated that hormone replacement therapy in post menopausal women may increase ovarian cancer incidence and mortality, especially in the group of women who have undergone HRT for more than 10 years. Physicians counselling women about HRT must consider the unique needs of each patient, and attempt to weigh the benefits and risks on an individual basis.