Ovarian cancer is among the most dreaded cancers since it is often found at a late stage where the opportunity for extended survival is poor. Ultrasound has been utilized in several ovarian cancer screening trials in asymptomatic women in order to detect ovarian cancer at early stages where survival rates are high. Efforts to improve screening for ovarian cancer are ongoing. While ovarian cancer screening in asymptomatic women is not recommended for clinical application currently, the care of women with adnexal masses found by ultrasound in clinical practice can benefit from close evaluation of the evidence obtained from large prospective ovarian cancer screening trials and by relating this evidence to recent advances in the understanding of different types of ovarian cancer. Post-menopausal women who have an adnexal mass discovered by ultrasound have a much higher risk of developing ovarian cancer than women with normal ultrasound. The preponderance of reported evidence indicates that ultrasound monitoring of an adnexal mass is safe, cost effective and can achieve an improved positive predictive value in detecting ovarian cancer when ovarian abnormalities resolve during surveillance. Proposals to arbitrarily discontinue ultrasound monitoring can negatively impact patient care and generate medical-legal actions, especially because there is no evidence to support safe discontinuation. In this review, we outline a rationale for continuing ultrasound surveillance of ovarian abnormalities.
A recent retrospective research article “Outcomes from Ultrasound Follow-up of Small Complex Adnexal Mass in Women over 50” states that repeated monitoring of a stable but persistent indeterminant lesion according to the Society of Radiologists in Ultrasound (SRU) Guideline is of questionable benefit based on the “fact that (1) no benefit has ever been demonstrated from long-term monitoring, (2) stability over time argues strongly against malignancy, (3) benign lesions are not generally precursors of malignant lesions, and (4) indefinitely repeated ultrasound monitoring exposes women to many of the same risks that are seen with ovarian cancer screening and as such may actually result in harm.” These authors state that monitoring adnexal masses beyond 7 months for the purpose of excluding malignant cause is of limited use. Our review of the literature shows otherwise. It should be noted that both the retrospective analysis by Suh-Burgmann et al and expert views from the SRU consensus conference are subject to different, as well as overlapping, levels of uncertainty.
A systemic literature review was conducted with the use of Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria to evaluate the quality of evidence, assess the key areas of uncertainty, and summarize the balance of benefits and harms of specific recommendations. The review criteria consisted of 88 PubMed searches that were conducted by a research librarian, of which 23 were used to focus findings that were based on various Boolean sorts (Literature search terms included ((((adnex* AND (ULTRASON* OR ULTRASOU*) AND (OUTCOME* OR RESULT* OR PROGNOS*))) OR ((((((((“Adnexa Uteri”[Majr]) OR “Adnexal Diseases”[Majr])) AND ((“ultrasonography” [Subheading]) OR “Ultrasonography”[Mesh]))) OR (((“Adnexal Diseases/ultrasonography”[Majr]) OR “Adnexa Uteri/ultrasonography”[Majr])))) AND “Prognosis”[Mesh]))) AND “Genital Neoplasms, Female/ultrasonography”[Majr] Filters: Humans; English; Middle Aged + Aged: 45+ years . Results before the year 2000 and any from nonrefereed journals were excluded. This yielded a total of 169 articles; quality was assessed with the use of a modified version of the Quality Assessment of Diagnostic Accuracy Studies assessment tool. Further review of the 169 articles for relevance for the prediction of ovarian malignancy based on ultrasound scans yielded 30 articles. The final aim of the search was to identify those original articles in which an ovarian mass that had been found by ultrasound scanning was evaluated for a risk of ovarian cancer. Articles were excluded if they were (1) letters to the editors, (2) case reports, or (3) duplicate reports from the same authors’ group. The significant reports referenced here are summarized with the use of GRADE ( Figure 1 ).
Serial ultrasound scanning leads to an improved positive predictive value for ovarian malignancy and a shift to detection at earlier stages. Malignancy has been found in apparently stable masses that eventually enlarged and increased in morphologic complexity in up to 3 years after initial detection. These results gleaned from 11,982 ultrasound examinations define the risks from terminating ultrasound surveillance. We have used the definition of acceptable risk level from environmental studies of no more than 1 extra death per 100,000 deaths to normalize the reported data. The absolute risks calculated from the United Kingdom Collaborative Trial of Ovarian Cancer Screening trial data for the appearance of malignancy in up to 3 years after an initial ultrasound examination are considerably elevated ( Figure 2 ). As judged by the 95% confidence intervals, the risk of malignancy is higher in any of the ovarian ultrasound abnormalities ( Figure 2 ). Allowing for a 10-fold relaxation of the 0.001% acceptable risk level would still predict a considerable number of extra malignancies within 3 years of the first scan. If ≥50% of these malignancies were diagnosed as advanced stage that are destined to be fatal, then the expectation for extra deaths because of curtailing surveillance is high and identifies the peril of limiting ultrasound surveillance. It is our opinion that continuing surveillance with serial ultrasound scans provides protection against these risks, while reducing the accrual of false-positives and the related unnecessary benign surgeries that would result if indeterminate masses that are destined to resolve are surgically removed rather than monitored.
