Ovarian Cancer: Prevalence in Incidental Simple Adnexal Cysts Initially Identified in CT Examinations of the Abdomen and Pelvis

Abstract

Purpose To evaluate the rate of malignancy in incidentally detected simple adnexal cysts at computed tomography (CT) to determine if simple-appearing cysts require follow-up. Materials and Methods In this HIPAA-compliant, institutional review board-approved retrospective cohort study, an institutional database was searched for abdominal and pelvic CT studies performed between June 2003 and December 2010 in women reported to have adnexal cysts. Adnexal cyst characterization was determined by prospective report description as well as image review by a research fellow and by a fellowship-trained abdominal radiologist for examinations with disagreement between the original report and the research fellow's assessment. Patients with known ovarian cysts or ovarian cancer at time of the index CT examination were excluded. Clinical outcome was assessed by using follow-up imaging studies, medical records, and the state cancer registry. Benign outcome was determined by benign findings at surgery, a decrease in size or resolution of a simple-appearing cyst at follow-up imaging, or stability of the cyst for at least 1 year. Descriptive statistics and 95% confidence intervals (CIs) were calculated. Results Among 42 111 women who underwent abdominal and pelvic CT examinations in the study period, 2763 (6.6%; 95% CI: 6.3%, 6.8%) (mean age, 48.1 years ± 18.1; range, 15-102 years) had a newly detected finding of ovarian cyst described in the body or impression section of the report. Median cyst size was 3.1 cm (range, 0.8-20.0 cm). Eighteen (0.7%; 95% CI: 0.4%, 1.0%) of 2763 patients were found to have ovarian cancer after an average follow-up of 5.1 years ± 3.8 (range, 0-12.8 years). None (95% CI: 0%, 0.4%) of 1031 women with simple-appearing cysts were given a diagnosis of ovarian cancer. This included none (95% CI: 0%, 0.4%) of 904 women with simple-appearing cysts with an adequate reference standard for benign outcome. Conclusion The prevalence of previously unknown adnexal cysts at CT was 6.6%, with an ovarian cancer rate of 0.7% (95% CI: 0.4%, 1.0%). All simple-appearing cysts were benign (95% CI: 99.6%, 100%). RSNA, 2017 Online supplemental material is available for this article.

Surveillance in Older Women With Incidental Ovarian Cysts: Maximal Projected Benefits by Age and Comorbidity Level

“…Although simple ovarian cysts in postmenopausal women have not been shown to confer an increased cancer risk, affected women frequently undergo follow-up imaging [5][6][7][8]. When considering women who were 66 years of age, we found that even if we assumed "perfect" ovarian cancer detection and cancer control during follow-up in such patients, the population-level LE benefit is very low, particularly for women of advanced age and who have comorbidities.…”

“…If we were able to incorporate such dependency, projected benefits of surveillance in corresponding sensitivity analysis would be even lower. Fourth, we do not specify a size threshold of cysts for women entering surveillance in our analysis because of heterogeneity in cyst size thresholds in studies addressing the malignant risk for cysts [5][6][7][8]. In general, smaller cysts (<5 cm) are more reliably evaluated on ultrasound; as such, consideration of reduction of follow-up recommendations is most valid for cysts of this size.…”

“…A subanalysis of ultrasound data from a large screening trial, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, demonstrated that postmenopausal women with simple ovarian cysts do not have an increased risk for ovarian cancer [6]. Large observational studies, including a nested case-control study of patients enrolled in Kaiser Permanente Washington [8], support the same conclusion [7,8], as does an observational study of CT data [5].…”

“…The prevalence of incidentally detected "simple" adnexal cysts (ie, cysts without wall thickening, nodularity, or septa) has increased with more frequent use of ultrasound and CT scans [4,5]. On ultrasound, the prevalence of simple adnexal cysts is 14% to 18% among postmenopausal women [6,7].…”

“…On ultrasound, the prevalence of simple adnexal cysts is 14% to 18% among postmenopausal women [6,7]. On CT, the prevalence is 7%, combining pre-and postmenopausal women [5]. A subanalysis of ultrasound data from a large screening trial, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, demonstrated that postmenopausal women with simple ovarian cysts do not have an increased risk for ovarian cancer [6].…”