Abstract

Is Cyclic Stimulation of the Breast Epithelium the Key Hormonal Factor Behind Breast Cancer?

Hakan Olsson

Exposure to many regular menstrual cycles during a life time or many cycles before first full term pregnancy may be a key factor behind the hormonal stimulation of the breast epithelium and the hormonal carcinogenesis. Most of the risk factor studies on the breast cancer and cycle characteristics were done before 2010. A consistent picture emerges that many regular cycles is an important risk factor and that early age at menarche, late menopause, few children, and late age at first full term pregnancy, short nursing and a short interval between onset of menses and establishment of regular menses may be surrogates for this risk. A majority of studies have been retrospective often using for cycles average cycle length recorded at one occasion. There is a great need to do large prospective studies following women for a life time. Valid data on menstrual cycle characteristics is needed for creating optimal risk factor models.