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Clinical classifiers, trials and the patient voice

Thursday May 13, 2021 - 20:20 to 21:00

Room: Breakout

P-4.5 Impact of hormone therapy use on survival outcomes of ovarian cancer in British Columbia

Alexandra M Lukey, Canada

Graduate Student
Department of Obstetrics and Gynecology
University of British Columbia



Impact of hormone therapy use on survival outcomes of ovarian cancer in British Columbia

Alexandra Lukey1,2, Gavin Stuart2, Gillian Hanley2.

1Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, BC, Canada; 2School of Nursing, University of British Columbia Okanagan, Kelowna, BC, Canada

Introduction: Ovarian cancer is the 8th leading cause of death in women worldwide. Ovarian cancer is considered a gynecologic cancer, but it is also classified as an endocrine cancer. Hormone replacement therapy (HRT) is a common strategy for improving postmenopausal women's quality of life. However, many women with OC and OC survivors are left untreated due to ambiguity in the evidence of the risks of using HRT after a diagnosis of OC. Some research has reported a modestly inverse association between hormone replacement therapy (HRT) and ovarian cancer survival, but these studies did not distinguish between different forms of HRT (e.g. estrogen-only (ET), progesterone-only (PT) or estrogen and progesterone (EPT)), lacked sufficient follow-up and were limited by small sample sizes.

Methods: We examined all women diagnosed with epithelial ovarian cancer between January 1st, 1996 and December 31st 2015, in British Columbia, Canada. Using cox proportional hazards regression to estimate the association of each hormone therapy exposure on ovarian cancer survival. We compared survival among 1) those using only ET; 2) those using PT or EPT with women who were unexposed to HRT.

Results: The group using ET only showed an increased risk of ovarian specific mortality as well as all-cause mortality (Ovarian specific mortality: Hazard ratio [HR] 1.45, 95% confidence interval [CI] 1.04 -2.01, All-cause mortality: [HR] 1.49, 95% [CI] 1.09-2.04). Conversely, the women on PT or EPT HRT showed improved survival outcomes, although these did not reach statistical significance (Ovarian specific: [HR] 0.84, 95% [CI] 0.63-1.11, All-cause mortality: Hazard ratio [HR] 0.81, 95% confidence interval [CI] 0.61-1.06).

Conclusions: This study presents evidence that outcomes in HRT use in OC vary dependent on hormone therapy variety. These findings contribute to the evidence of the safety and possible benefit of specific HRT regimens in ovarian cancer patients and survivors.

Canadian Institute of Health Research. University of British Columbia.

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