Evidence-Based Approach to MenopauseBreast Cancer and Hormonal TherapyCONNER, PETER, MD, PhD; LUNDSTRÖM, EVA, MD, PhD; VON SCHOULTZ, BO, MD, PhDAuthor Information Department of Obstetrics and Gynecology, Karolinska University Hospital, Stockholm, Sweden Source of Funding: Supported by grants from the Swedish Research Council, the Stockholm County Council and the Karolinska Institutet. Correspondence: Bo von Schoultz, MD, PhD, Department of Obstetrics and Gynecology, Karolinska University Hospital, SE-171 76 Stockholm, Sweden. E-mail: email@example.com Clinical Obstetrics and Gynecology: September 2008 - Volume 51 - Issue 3 - p 592-606 doi: 10.1097/GRF.0b013e318180b8ed Buy Metrics Abstract Valid evidence from randomized-controlled trials indicates that breast cancer risk is increased with combined estrogen/progestogen use and that such treatment implies a risk greater than that of estrogen alone. Overall, risk estimates from observational studies are somewhat higher than in randomized-controlled trials but remain modest as compared with other risk factors even after long-term treatment. For combined estrogen/progestogen therapy, risk increases gradually to reach statistical significance after 4 to 5 years. Apart from its many beneficial health effects, the safety data for use of estrogen alone are quite reassuring. The only justifications for progestogen addition are for bleeding control and endometrial protection. At present, there are several new therapeutic compounds and concepts in development, which hold promise to provide both endometrial protection and breast safety. © 2008 Lippincott Williams & Wilkins, Inc.