Reduced breast cancer incidence in women treated with subcutaneous testosterone, or testosterone with anastrozole: A prospective, observational study

T and/or T + A, delivered subcutaneously as a pellet implant, reduced the incidence of breast cancer in pre and postmenopausal women. Evidence supports that breast cancer is preventable by maintaining a T to estrogen ratio in favor of T and, in particular, by the use of continuous T or, when indicated, T + A. This hormone therapy should be further investigated for the prevention and treatment of breast cancer.