Several recent studies show that most breast cancer patients should take tamoxifen for five years. Estrogen can spread a preexisting breast cancer.
Tamoxifen is a drug that blocks estrogen.
However, tamoxifen can cause uterine cancer, but, it prevents far more breast cancer recurrences than it causes uterine cancers. Until recently, doctors didn't know how long women with breast cancer should take tamoxifen. I'm Dr. Gabe Mirkin on Fitness. Five versus more than five years of tamoxifen therapy for breast cancer patients with negative lymph nodes and estrogen receptor-positive tumors. LE Rutqvist, T Hatschek, S Ryden, J Bergh, NO Bengtsson, J Carstenssen, B Nordenskjold, A Wallgren.