cancers Review Menopausal Hormone Therapy and Risk of Endometrial Cancer: A Systematic Review Clemens B. Tempfer 1,* , Ziad Hilal 1, Peter Kern 2, Ingolf Juhasz-Boess 3 and Günther A. Rezniczek 1 1 Department of Gynecology and Obstetrics, Ruhr-Universität Bochum, Bochum, Germany and Comprehensive Cancer Center of the Ruhr-Universität Bochum (RUCCC), 44708 Bochum, Germany;
[email protected] (Z.H.);
[email protected] (G.A.R.) 2 Department of Gynecology and Obstetrics, St. Elisabeth-Krankenhaus Bochum, 44787 Bochum, Germany;
[email protected] 3 Department of Gynecology and Obstetrics, University of Freiburg, 79110 Freiburg, Germany;
[email protected] * Correspondence:
[email protected] Received: 18 July 2020; Accepted: 5 August 2020; Published: 6 August 2020 Abstract: Background: Menopausal hormone therapy (MHT) is an appropriate treatment for women with the climacteric syndrome. The estrogen component of MHT effectively alleviates climacteric symptoms but also stimulates the endometrium and thus may increase the risk of endometrial cancer (EC). Materials and Methods: We performed a systematic literature search of the databases PubMed and Cochrane Central Register of Controlled Trials to identify controlled and uncontrolled clinical trials reporting on the prevalence and/or incidence of EC among women using MHT. Results: 31 publications reporting on 21,306 women with EC diagnosed during or after MHT were identified. A significantly reduced risk of EC among continuous-combined (cc)MHT users with synthetic progestins (SPs) was demonstrated in 10/19 studies with odds ratios (ORs)/hazard ratios (HRs) between 0.24 and 0.71. Only one study documented an increased risk of EC among long-term users ( 10 years), not confirmed in three other sub-group analyses of women with 6, 5, and >10 years ≥ ≥ ≥ of ccMHT use.