The role of three-dimensional volume measurement in diagnosing endometrial cancer in patients with postmenopausal bleeding.

ABSTRACT

OBJECTIVE: To evaluate the role of three-dimensional transvaginal ultrasound in diagnosing endometrial cancer in patients with history of postmenopausal bleeding and compare its effectiveness with two-dimensional ultrasound. METHODS: Transvaginal ultrasound examinations, diagnostic hysteroscopy with subsequent curettage, and/or hysterectomy were performed in 213 consecutive patients with a history of postmenopausal bleeding. The results of the ultrasonographic examinations were compared with the diagnoses on the basis of histologic examination. In addition to an explorative data analysis, receiver operating characteristic curves were shown and areas under curves were calculated. Minimal endometrial volume (2.7 ml) and minimal endometrial thickness (7 mm) of endometrial carcinoma were defined as optimal cutoff values. RESULTS: In 42 patients, endometrial carcinoma was diagnosed. The mean endometrial volume of patients with endometrial cancer, measured by three-dimensional ultrasound, was 11.78 ml. The sensitivity of the endometrial volume at the optimal cutoff (2.7 ml) was 100.00%, the specificity was 69.00%, the positive predictive value was 44.20%, and the negative predictive value was 100.00%. On two-dimensional ultrasound, the mean endometrial thickness of patients with endometrial cancer was 16.6 mm. The sensitivity endometrial thickness measurements at the optimal cutoff (7 mm) was 100.00%, the specificity was 43.3%, the positive predictive value was 30.2%, and the negative predictive value was 100.00%. The area under curve of volume measured by three-dimensional ultrasound was 0.89 (95% CI 0.85-0.93). The area under curve of endometrial thickness was 0.85 (95% CI 0.80-0.91). The comparison of the area under curve of receiver operating curves between endometrial volume and endometrial thickness revealed a significant difference (p=0.023). CONCLUSION: Volume measurement by three-dimensional transvaginal ultrasound has a higher specificity, which means that it has the ability to better identify the negative cases compared to conventional ultrasound. Three-dimensional transvaginal ultrasound is a helpful tool for diagnosing endometrial cancer in patients with postmenopausal bleeding.