Variables Associated with Resolution and Persistence of Ovarian Cysts

By Katrina Rapp, BA, and Maria I. Rodriguez, MD, MPH

Katrina Rapp is an MD candidate, Oregon Health & Science University, Portland, and Dr. Rodriguez is Professor, Obstetrics & Gynecology, Division of Complex Family Planning, Department of Obstetrics & Gynecology, Oregon Health & Science University, Portland.

SYNOPSIS: This prospective cohort study evaluated 2,683 individuals with incidental cysts discovered during ovarian cancer screenings to determine what factors are associated with cyst resolution over time. Characteristics such as smaller cysts, septated cysts, younger age, premenopausal status, and family history of ovarian cancer were associated with an increased percentage of cyst resolution overall, and factors including older age and lack of hormone therapy were associated with a faster rate of cyst resolution over time. The findings of this study indicate that different surveillance times may be appropriate, depending on cyst morphology and patient characteristics.

SOURCE: Lasher A, Harris LE, Solomon AL, et al. Variables associated with resolution and persistence of ovarian cysts. Obstet Gynecol 2023; Oct 12. doi: 10.1097/AOG.0000000000005411. [Online ahead of print].

Ovarian cysts are common and frequently discovered incidentally on pelvic imaging, often presenting a challenge for providers in determining appropriate length of surveillance time. For cysts with malignant features, surgical intervention is warranted. While most ovarian cysts are benign and typically will resolve on their own, serial surveillance is recommended to rule out malignant transformation and document resolution.^1,2 However, there is no established duration for length of serial surveillance, which creates challenges for physicians in determining when surgical intervention is warranted. The University of Kentucky Ovarian Cancer Screening Trial (UK-OCST) addressed this gap in the literature by evaluating how ovarian cyst resolution time varies depending on cyst morphology and patient characteristics.

Benign ovarian cysts or masses often are associated with hormonal changes that affect the ovarian follicles and can manifest as a fluid-filled sac either within or on the surface of an ovary. Transvaginal ultrasound (TVUS) is the imaging modality of choice for adnexal pathology, and imaging findings that suggest benign cyst pathology include smooth and thin walls, lack of solid components and septations, and minimal internal blood flow.^2,3 Although the American College of Obstetricians and Gynecologists recommends repeat imaging without surgical intervention for simple cysts smaller than 10 cm in diameter, there is no established timeframe for serial surveillance.³

In this prospective cohort study at the University of Kentucky, 47,762 individuals were screened for ovarian cancer using TVUS examinations from 1987 to 2019 and enrolled in a prospective cohort study. Eligibility criteria for this study included asymptomatic postmenopausal individuals aged 50 years or older and premenopausal individuals between ages 25 to 50 years who had, at minimum, the same expected risk of ovarian cancer as postmenopausal individuals because of family history, personal breast cancer gene (BRCA) status, Ashkenazi background, or Lynch syndrome. Only individuals with both visible and normal-appearing ovaries on their first visit were included in the study. From these patients, 2,638 individuals were found to have incidental cysts and were evaluated further. There was an average of 6.7 screening encounters per person, with a mean follow-up of 7.9 years.

UK-OCST researchers visualized cyst persistence using Kaplan Meier curves for univariate analysis and Cox regression models for multivariate analysis among individuals with cysts nested within groupings (menopausal status, unilocular vs. septate cysts, and hormone therapy [HT] use). Chi-square and t-tests were used for the tests of association among subgroups. Out of the 2,638 individuals found to have incidental ovarian cysts, 63.2% experienced resolution within 1.2 years.

This study found that aspects of cyst morphology and various patient characteristics were associated with cyst resolution. For cyst morphology, unilocular and septated cysts smaller than 3 cm resolved faster than cysts larger than 6 cm (P < 0.05), with median time to resolution being 1 year and 3.5 years, respectively. Unilocular cysts took longer to resolve compared to septated cysts (median of 1.5 years and one year, respectively; P > 0.5). When assessing patient characteristics, it was found that younger age and premenopausal status (excluding synchronous bilateral cysts) were associated with greater likelihood of cyst resolution (P < 0.05). However, cyst resolution time takes significantly longer in younger individuals than in individuals older than 70 years of age (P < 0.05). For individuals aged younger than 40 years, 40-69 years, and older than 70 years, median cyst resolution times were 1.8 years, 1.25 years, and one year, respectively (P < 0.05). Additionally, lack of HT use was associated with faster resolution time when compared to those using HT, with a median resolution time of 1.17 years and two years, respectively (P < 0.05). There was no significant difference in time to resolution based on body mass index or family history of ovarian cancer.⁴

COMMENTARY

The American College of Obstetricians and Gynecologists currently recommends repeat imaging without surgical intervention for benign-appearing ovarian cysts up to 10 cm in size; however, the appropriate timeframe for surveillance had not previously been established, creating a clinical challenge of how long to continue monitoring people.^3,4 UK-OCST contributes to the existing literature by providing guidance for follow-up management of incidental ovarian cysts, depending on patient characteristics and cyst morphology.

For clinicians in practice, the authors recommended that the surveillance of incidental ovarian cysts should continue for as long as three to four times the expected median resolution time determined in this study. This rationale is based on the fact that the multiplier of three to four includes the entirety of the distribution of time over which incidental cysts resolved. To provide an example, HT users were found to have a two-year median resolution time of cysts, so six to eight years of follow-up should predict the resolution of all cysts in these individuals using HT. Clearly, when there is high suspicion of malignancy, referral to gynecologic oncology for further evaluation and consideration of surgical intervention should be pursued.

REFERENCES

1. Farghaly SA. Current diagnosis and management of ovarian cysts. Clin Exp Obstet Gynecol 2014;41:609-612.
2. Modesitt SC, Pavlik EJ, Ueland FR, et al. Risk of malignancy in unilocular ovarian cystic tumors less than 10 centimeters in diameter. Obstet Gynecol 2003;102:594-599.
3. American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Gynecology. Practice Bulletin No. 174: Evaluation and management of adnexal masses. Obstet Gynecol 2016;128:e210-e226.
4. Lasher A, Harris LE, Solomon AL, et al. Variables associated with resolution and persistence of ovarian cysts. Obstet Gynecol 2023; Oct 12. doi: 10.1097/AOG.0000000000005411. [Online ahead of print].