TRANSVAGINAL ULTRASOUND FOR ENDOMETRIAL CANCER SCREENING?

December 13, 2010 — Among a cohort of postmenopausal women, endometrial thickness and abnormalities determined by screening with transvaginal ultrasound (TVS) can predict the risk for endometrial cancer and atypical endometrial hyperplasia (AEH), according to the findings of a large-scale, nested case-control study.

Ian Jacobs, MD, from the Department of Gynaecological Oncology at University College London, in the United Kingdom, and colleagues reported their findings online December 13 in The Lancet.

The current study was the first large-scale study designed to determine the efficacy of TVS as a screening test for endometrial cancer and AEH. According to the researchers, TVS screening for endometrial cancer and AEH has a high level of sensitivity and may have "immediate value in the management of increased endometrial thickness in postmenopausal women undergoing pelvic scans for reasons other than vaginal bleeding."

A total of 48,230 women from the general population underwent TVS to determine endometrial thickness and abnormalities in the United Kingdom Collaborative Trial of Ovarian Cancer Screening prevalence screen; data from 36,867 women were included in the study. Of the women included in the cohort, 136 developed endometrial cancer or AEH within 1 year of TVS.

Increased endometrial thickness was associated with a higher risk for developing endometrial cancer or AEH. The optimum endometrial thickness cutoff for endometrial cancer or AEH was 5.15 mm, with a sensitivity of 80.5% (95% confidence interval [CI], 72.7% - 86.8%) and specificity of 86.2% (95% CI, 85.8% - 86.6%).

Sensitivity and specificity at a 5-mm or higher cutoff were 80.5% (95% CI, 72.7% - 86.8%) and 85.7% (95% CI, 85.4% - 86.2%), respectively, whereas for women with a 5-mm or higher cutoff and endometrial abnormalities, the sensitivity and specificity were 85.3% (95% CI, 78.2% - 90.8%) and 80.4% (95% CI, 80.0% - 80.8%), respectively. For a cutoff of 10 mm or higher, sensitivity and specificity were 54.1% (95% CI, 45.3% - 62.8%) and 97.2% (95% CI, 97.0% - 97.4%).

The researchers concluded that TVS screening is efficacious in predicting the development of endometrial cancer and AEH within 1 year of the screening test among postmenopausal women. Improved sensitivity and specificity can be achieved by limiting screening to a higher-risk group using an endometrial thickness cutoff of 5 mm or higher.

Because of a lack of large-scale studies, Dr. Jacobs and colleagues "do not advocate population screening for endometrial cancer until further data are available." However, they note that the "extra cost of incorporating endometrial cancer screening within the scope of an ovarian cancer screening trial could be marginal and add benefit to the screening strategy," which could greatly assist in the prediction and early treatment of endometrial cancer and AEH.

Does Early Detection of EC and AEH Improve Survival?

In an editorial, Ignace Vergote, MD, PhD, and colleagues, from the Department of Gynaecologic Oncology, University Hospitals Leuven, in Belgium, agree with Dr. Jacobs and associates that endometrial cancer survival rates, stage by stage, match those of ovarian cancer. However, the editorialists point out that endometrial cancer generally presents clinically at early stages primarily as a result of the associated postmenopausal bleeding. In addition, they state, there is no known benefit to earlier, asymptomatic detection.

Limitations of the trial described in the editorial include endometrial cut-offs that are not consistent with earlier research, potential bias in the reporting of bleeding associated with endometrial thickness found on TVS, and lack of reporting of other risk factors for endometrial cancer such as family history, diabetes, hypertension, and smoking.

Dr. Vergote and colleagues write, "Clinicians should be aware that the study by Jacobs and colleagues does not prove a benefit for screening for endometrial cancer because of an absence of survival data."

Further, they go on to explain, "the only study that assessed 5-year disease-free survival did not find any improvement in patients with screen-detected endometrial cancers compared with symptomatic patients who had less than 8 weeks of postmenopausal bleeding before their first visit." They conclude that "the study by Jacobs and colleagues provides important ultrasonographic endometrial findings in asymptomatic postmenopausal women, but screening for endometrial cancer with ultrasonography has not been sufficiently proven to be beneficial because of the high cost, the prevalence of cancers that are not clinically relevant or hyperplasia, the number of unnecessary surgical interventions and associated morbidity, the presence of clinically detected symptoms such as bleeding that happen at an early stage in many women with endometrial cancer, show a survival benefit in screened patients."

The study was supported by the UK Medical Research Council, Cancer Research UK, the UK Department of Health, and the Eve Appeal. Dr. Jacobs serves as a consultant for Becton Dickinson; he and one other author also have financial interests through University College London Business and Abcodia Ltd. The other authors and the editorialists have disclosed no relevant financial relationships.

Lancet. Published online December 13, 2010.