Incidence, Risk Factors, and Natural History of Ovarian Cysts in Postmenopausal Chinese Women: a Retrospective Cohort Study

Abstract

Objective: To evaluate the incidence of and risk factors for ovarian cysts in postmenopausal Chinese women, and the resolution rate of various morphological cysts and their association with ovarian cancer with use of serum CA-125 level and risk of malignancy index (RMI).
Methods: This was a retrospective cohort study conducted at a regional hospital in Hong Kong. All women who were first assessed in our clinic from May 2014 to January 2016 were included. We reviewed the ultrasound reports of their 6- to 9-monthly interval rescan, as well as the demographics, clinical history, and ultrasound findings of women who presented with postmenopausal bleeding. For women with any ovarian cysts on rescans or in surgery,
ultrasonographic findings on interval scans and pathological reports from surgery up to 1 year were reviewed.
Results: A total of 1158 Chinese women were included. The overall incidence of ovarian cysts on a single ultrasound scan was 6.6%. The age-related incidence increased after 50 years of age and peaked at 60 to 64 years, then dropped until a second peak occurred at 75 to 79 years of age. No other potential risk factors for an increased incidence of ovarian cysts were identified. Chance of resolution of simple cysts was 26% in a single rescan. The resolution rate for a non-simple cyst was low (6%). All ovarian cysts with RMI score of <200 were benign. A RMI score of ≥200 was associated with a higher risk of ovarian cancer.
Conclusion: The resolution rate of ovarian cysts was comparable with that of overseas studies. Current management guidelines from overseas are appropriate for the Chinese population. The age-related incidence of post-menopausal cysts among Chinese women may support focusing on a target age-group in the population if a screening programme were to be implemented. Further prospective studies are warranted.