Association Between Menopausal Estrogen-Only Therapy and Ovarian Carcinoma Risk

Abstract

Authors:
 ¹Departments of Preventive Medicine and Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, California; the University of Texas School of Public Health, Houston, Texas; the Obstetrics and Gynecology Epidemiology Center, Brigham and Women's Hospital, and the Harvard T. H. Chan School of Public Health, Boston, Massachusetts; the Department of Public Health Sciences, the University of Virginia, Charlottesville, Virginia; the Division of Cancer Epidemiology, German Cancer Research Center, Heidelberg, and the University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; the Department of Epidemiology, the Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Women's Cancer, Institute for Women's Health, University College London, London, United Kingdom; the Center for Cancer Prevention and Translational Genomics and Cancer Prevention and Control, Samuel Oschin Comprehensive Cancer Institute, the Department of Biomedical Sciences, and the Community and Population Health Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California; the Department of Chronic Disease Epidemiology, Yale University School of Public Health, New Haven, Connecticut; the Department of Obstetrics, Gynecology, and Reproductive Sciences, Division of Gynecologic Oncology, University of Pittsburgh School of Medicine, the Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, and the Women's Cancer Research Program, Magee-Womens Research Institute and University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania; the Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Buffalo, New York; the Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, North Carolina; the Department of Epidemiology, University of Washington, and the Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington; the Department of Virus, Lifestyle and Genes, Danish Cancer Society Research Center, and the Molecular Unit, Department of Pathology, Herley Hospital, and the Department of Gynecology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; the Cancer Epidemiology Program, University of Hawaii Cancer Center, and the Department of Obstetrics and Gynecology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii; the Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York; and the Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan.

OBJECTIVE: To describe the association between postmenopausal estrogen-only therapy use and risk of ovarian carcinoma, specifically with regard to disease histotype and duration and timing of use.

METHODS: We conducted a pooled analysis of 906 women with ovarian carcinoma and 1,220 women in a control group; all 2,126 women included reported having had a hysterectomy. Ten population-based case-control studies participating in the Ovarian Cancer Association Consortium, an international consortium whose goal is to combine data from many studies with similar methods so reliable assessments of risk factors can be determined, were included. Self-reported questionnaire data from each study were harmonized and conditional logistic regression was used to examine estrogen-only therapy's histotype-specific and duration and recency of use associations.

RESULTS: Forty-three and a half percent of the women in the control group reported previous use of estrogen-only therapy. Compared with them, current or recent estrogen-only therapy use was associated with an increased risk for the serous (51.4%,) and endometrioid (48.6%,) histotypes. In addition, statistically significant trends in risk according to duration of use were seen among current or recent postmenopausal estrogen-only therapy users for both ovarian carcinoma histotypes (Ptrend<.001 for serous and endometrioid). Compared with women in the control group, current or recent users for 10 years or more had increased risks of serous ovarian carcinoma (36.8%,) and endometrioid ovarian carcinoma (34.9%,).

CONCLUSION: We found evidence of an increased risk of serous and endometrioid ovarian carcinoma associated with postmenopausal estrogen-only therapy use, particularly of long duration. These findings emphasize that risk may be associated with extended estrogen-only therapy use.