Several studies are ongoing and new ones are planned.
A Scandinavian multicenter study will include about 1300 women who have been diagnosed with in situ or early stage breast cancer. These women usually have more severe menopausal symptoms because they had to stop taking hormones suddenly. Thus, researchers can find out if women receiving HRT therapy develop any harmful effects, such as early return of breast cancer or appearance of a second cancer. A randomized trial means that each woman in the study is given either one therapy or another based on a random assignment, using a method like a coin toss. One study will test whether it is safe to add HRT to tamoxifen use in an attempt to relieve estrogen deficiency symptoms.