A new, comprehensive study by scientists at the Institute of Cancer Research in London followed 39,000 women on hormone therapy for 6 years showed that estrogen-only therapy showed no overall increase in breast cancer risk compared with women who had never used HRT. This type of therapy can be safely prescribed to women who no longer have a uterus. However, those using combined HRT, a combination of estrogen and progestogen, had a 2.7 times greater risk than non-users, significantly higher than previously reported. This is the type of hormone therapy that can be prescribed to women who have not had a hysterectomy. Estrogen-only therapy can negatively affect the uterus and requires progesterone to balance out the effects. Estrogen therapy alone can increase the risk of uterine cancer.
The implications for women who have GYN conditions that would benefit from a minimally invasive hysterectomy are now two-fold. In addition to treating a condition like fibroids, or adenomyosis, a hysterectomy opens a woman up to a safer form of HRT when she reaches menopause.