Hello. I am Dr Andrew Kaunitz, professor and associate chair in the Obstetrics/Gynecology Department of the University of Florida College of Medicine in Jacksonville, Florida. Today I want to discuss menopausal hormone therapy (HT) and the risk for ovarian cancer.
Although studies of systemic HT and ovarian cancer risk have not yielded definitive answers, detecting any real effect of HT on this uncommon but lethal disease would be important. In February 2015, investigators published a meta-analysis of data from available epidemiologic studies to assess the impact of HT on ovarian cancer risk, focusing on prospective studies.[1]
The authors observed that risk for ovarian cancer was modestly higher in HT ever-users than never-users, with a relative risk of 1.2, and they implied that this association represents cause and effect. I am skeptical, however.
HT use was associated with elevated risks for serous and endometrioid tumors but not mucinous tumors; in fact, HT use was associated with lower risk for clear-cell tumors. Surprisingly, risks were similar for combination estrogen-progestin and estrogen-only HT.
Too Many Uncertainties
The most important criterion for judging cause and effect is strength of the association.[2] Decades ago, the association between estrogen therapy and endometrial cancer was determined to be strong, with an odds ratio > 7, and biologically plausible.[3] In the present meta-analysis, relative risks were all ≤ 1.6, and thus should be considered "weak associations," difficult to interpret in observational studies such as the data that this meta-analysis is based on.[2]
Furthermore, the limited biological plausibility of the observed associations should prompt caution. Clinical trial data have clarified that, compared with menopausal estrogen-progestin therapy, estrogen-only therapy affects risk for endometrial and breast cancer in distinctly different ways.
Finally, the temporal trends in risk associated with HT use do not appear consistent with our understanding that carcinogenesis occurs over an extended period. The risks in current users who had used HT for less than 5 years were higher than those in recent users who had used HT for 5 years or more. Given all of these uncertainties, I view the conclusions of this meta-analysis with caution.
Thank you. I am Andrew Kaunitz.
Medscape Ob/Gyn © 2015 WebMD, LLC
Cite this: Menopausal Hormone Therapy and Risk for Ovarian Cancer - Medscape - Mar 24, 2015.
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