Variables Associated With Resolution and Persistence of Ovarian Cysts

Ovarian cysts are relatively common and can occur throughout a lifetime. Benign cysts are typically fluid-filled, without septations or solid features, and can form either inside or on the surface of the ovary. Ovarian cysts are typically diagnosed using transvaginal ultrasonography, which is very effective, accurate, and low-cost as well as well-tolerated by patients. Management of benign cysts varies from practitioner to practitioner, but guidelines recommend surveillance for cysts less than 10 cm in diameter and surgical intervention for larger cysts or when malignancy is suspected. Although surveillance is the only recommendation in most cases, there is no established pattern for the frequency of surveillance or when surgical management becomes necessary in any particular case. This study was designed to identify factors associated with cyst resolution to help practitioners make decisions about timing and length of surveillance for ovarian cysts. Data for this study were obtained from the University of Kentucky Ovarian Cancer Screening Trial, which enrolled patients from November 1987 to March 2019. Inclusion criteria were asymptomatic postmenopausal patients older than 50 years and premenopausal patients between the ages of 25 and 50 years with the same expected risk for cancer as patients older than 50 years. Exclusion criteria were those with prevalent cysts, a known complex or solid ovarian mass, or a personal history of ovarian cancer. The final sample included 47,762 patients and 321,566 transvaginal ultrasonography examinations over the 31 years of the study. The average patient underwent 6.7 screenings, and the mean follow-up was 7.9 (SD, 0.04) years. After exclusions for surgery and prevalent cysts, 37,873 individuals never had cysts, and 2638 had new cysts and were classified as the incident group. Of the incident group, 1667 had their cysts resolved, with 1037 individuals postmenopausal and 630 premenopausal. Those with persistent cysts consisted of 281 premenopausal individuals and 690 postmenopausal. Premenopausal patients had a greater proportion of cyst resolution compared with postmenopausal patients, which held true in subgroups with unilateral, bilateral, and asynchronous bilateral cysts (P < 0.05), but not for the subgroup with synchronous bilateral cysts. Septated cysts generally resolved more quickly than unilocular cysts, with a mean resolution time of 1.89 and 2.58 years, respectively (P < 0.001). Mean resolution time of all cysts in the incident group was 14.4 months, with 63.2% of cysts having resolved within a year of diagnosis. Those with resolution of cysts were, on average, younger than those with persistent cysts (P < 0.05), and resolution time was dependent on cyst size. Additionally, those using hormone therapy during the study were more likely to have persistent cysts (P < 0.05). Resolution time of cysts was not significantly associated with menopausal status, body mass index (BMI), or family history of ovarian cancer. Multivariate analysis showed that septated cysts were more likely than unilocular cysts to resolve (hazard ratio, 1.46; 95% confidence interval, 1.35–1.59), with a decreased hazard for resolution dependent on size. In addition, postmenopausal individuals were less likely to experience resolution of cysts (hazard ratio, 0.67; 95% confidence interval, 0.58–0.77). These results indicate that cysts smaller than 3 cm resolve more quickly than larger cysts and that BMI and family history of ovarian cancer do not affect resolution time. These results describe how cyst characteristics in addition to hormone therapy use, age, menopausal status, BMI, and family history of ovarian cancer affect resolution times, which can help inform practitioners about the length of time a particular patient may need to be monitored. Future research should be focused on methods of reducing resolution time as well as potentially influencing factors not examined here. Additionally, the sample should eventually be expanded beyond those who are at higher risk of ovarian cancer than the general population.