Am Fam Physician. 1998;58(6):1458-1460
Although endometrial biopsy is a relatively sensitive method for identifying endometrial cancer and its precursors, it is unreliable for identifying endometrial polyps and submucous fibroids. The addition of hysteroscopy increases the sensitivity for finding intraluminal masses. To perform sonohysterography, sterile saline solution is instilled into the uterus to increase the visualization of intraluminal masses. O'Connell and associates conducted a prospective, controlled trial to compare the diagnostic reliability of transvaginal sonohysterography and endometrial biopsy with fractional curettage and hysteroscopy in the initial evaluation of postmenopausal bleeding.
The study included 100 postmenopausal women with abnormal uterine bleeding who ranged in age from 42 to 80 years (mean age: 59.7 years). An endometrial biopsy was performed at the time of initial evaluation in all patients. Transvaginal ultrasonography was then performed to measure endometrial stripe thickness, the uterus and ovaries. This was immediately followed by sonohysterography to evaluate the endometrial wall thickness and identify any intraluminal masses. A fractional curettage at the time of operative hysteroscopy was used to obtain a histologic sample. The histologic results were compared with the diagnoses obtained by endometrial biopsy and sonohysterography. Histopathologic examination revealed atrophic or proliferative changes in 52 percent of the patients. Five patients had endometrial cancer.
The mean endometrial thickness for the entire group was 7.6 mm. It was significantly thinner (4.4 mm) in patients with endometrial atrophy. Conversely, endometrial thickness was 10.0 mm in patients diagnosed with submucosal fibroids and 17.7 mm in patients diagnosed with adenocarcinoma.
The combination of endometrial biopsy and transvaginal sonohysterography had a 95 percent positive correlation with the surgical pathologic findings. The use of this approach to evaluate women with postmenopausal vaginal bleeding was 94 percent sensitive and 96 percent specific, with positive and negative predictive values of 96 and 94 percent, respectively. In only five of the 100 patients did the ultrasonographic report not correlate with the surgical findings.
Data revealed a disproportionate number of false-negative and false-positive results among the eight patients receiving tamoxifen. If these patients were excluded from the analysis, the positive correlation increased to 97 percent and the sensitivity and specificity to 95 and 98 percent, respectively.
Neither endometrial biopsy nor measurement of endometrial thickness was reliable as a single diagnostic approach. However, endometrial biopsy did have a high specificity with a high positive predictive value. Transvaginal sonohysterography had a sensitivity of 86 percent and a specificity of 100 percent for identification of an intraluminal mass. However, sensitivity would have been noticeably hampered without an endometrial biopsy.
The authors conclude that transvaginal sonohysterography accurately identifies intraluminal uterine masses.Although some studies have suggested that endometrial thickness can be used as a means of excluding cancer, nine patients in this study with an endometrial thickness of less than 5 mm had significant endometrial pathologic findings, including adenocarcinoma. If these patients had been treated expectantly on the basis of benign findings on endometrial biopsy and an endometrial thickness of less than 5 mm, it is likely that they would have experienced continued bleeding. Neither transvaginal ultrasonography nor endometrial biopsy by themselves appear to be reliable tools for evaluating postmenopausal vaginal bleeding. Endometrial biopsy combined with sonohysterography was an accurate means of identifying patients who did not require further surgical intervention.
editor's note: Although uterine curettage has been considered the “gold standard” for the evaluation of abnormal uterine bleeding, its limitations must be realized. Blind sampling of the endometrium can miss intraluminal masses. If postmenopausal women with vaginal bleeding are to be managed expectantly, the clinician must have a reliable method of identifying the etiology of the bleeding to confidently allow medical management rather than surgical intervention.—b.a.