J Clin Ultrasound 24:79-82, February 1996 0 1996 by John Wiley & Sons, Inc. CCC 0091-27511961020079-04

The Sensitivity and Specificity of Vaginal Sonography in Detecting Endometrial

Abnormalities in Women with Postmenopausal Bleeding

Igal Wolman, MD,* Joseph Sagi, MD,* Shimon Ginat, MD,* Ariel J. Jaffa, MD,? Joseph Hartoov, MD,? and Gideon Jedwab, MD*

Abstract: Objective: To evaluate the sensitivity and specificity of vaginal sonography in the detection of endometrial abnormalities in patients with postmenopausal bleeding (PMB).

Methods: In a prospective study, 54 patients with PMB were examined with vaginal ultrasonography prior to dilatation and curettage. The mean endometrial thickness was compared with the histopathological results. A cutoff value of 5 mm was prospec- tively chosen to evaluate the sensitivity and specificity of this method.

Results: The calculated sensitivity for the measurement of endometrial thickness as a predictor of endometrial pathology was 89%, and the specificity was 83%. We found carcinoma associated with an endometrial thickness of 6 mm.

Conclusions: Although its sensitivity was high, we feel that an endometrial thick- ness >5 mm should constitute a cause for concern but not a definitive indication of pathology. Thus we believe that, at this point, the role of vaginal sonography as an aid in determining which women with PMB should undergo curettage has yet to be deter- mined. 0 1996 John Wiley & Sons, Inc. Indexing Words: Endometrial abnormalities . Vaginal sonography . Transvaginal ultrasonography

Approximately 80% of endometrial cancers occur in postmenopausal women.’ The major clinical warning sign for endometrial cancer is postmeno- pausal bleeding (PMB). Postmenopausal bleeding has, therefore, always been an absolute indica- tion for curettage. Benign conditions are usually found in the majority of cases of PMB on whom curettage is performed. Thus, the majority of pa- tients are unnecessarily exposed to a procedure that carries some risk of morbidity and even death.2

The introduction of transvaginal ultrasonogra-

From the Departments of Obstetrics and Gynecology *“B” and YA, Tel Aviv Sourasky Medical Center, Serlin Maternity Hospital, and Sackler Faculty of Medicine, Tel Aviv Univer- sity, Israel. For reprints contact I. Wolman, MD, Department of Obstetrics and Gynecology “B”, Serlin Maternity Hospital, P.O. Box 7079, Tel Aviv 61070, Israel.

VOL. 24, NO. 2, FEBRUARY 1996

phy has allowed a better visualization of small changes in the endometrial ~ t r u c t u r e . ~ , ~ There- fore, several authors have suggested that vagi- nosonography may serve as a tool for the detec- tion of endometrial ~ a n c e r . ~ - ~

We undertook this prospective study to evalu- ate the sensitivity and specificity of the current recommended guidelines for vaginal sonography as a diagnostic tool for the detection of endome- trial cancer in patients with PMB.

MATERIALS AND METHODS

In a prospective study, 54 women with PMB were examined by transvaginal ultrasonography prior to dilatation and curettage (D & C).

Inclusion criteria were: amenorrhea for at least a year with follicle stimulating hormone values of >30 IU/mL, no estrogen replacement therapy

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WOLMAN ET AL.

used during menopause, and no pelvic abnormal- ity detected by ultrasound.

Immediately prior to the D & C, a vaginal ul- trasonographic examination was performed with the empty bladder technique. All the examina- tions were performed in the lithotomy position, with a transvaginal 5 mH mechanical sector transducer (Elscint 1000, Haifa, Israel) by the same physician (Dr. J.S.). The transducer was in- troduced into the posterior vaginal fornix when the uterus was retroverted and into the anterior vaginal fornix when i t was anteverted. The uterus was scanned longitudinally and trans- versely. Endometrial thickness was measured at the broadest diameter in the longitudinal plane (Figure 1). The measurements included both en- dometrial layers. Dilatation and curettage was then performed in the department by an experi- enced gynecologist.

The histopathological results were divided into several groups, and the mean longitudinal thick- ness was calculated for each group. The mean en- dometrial thickness was compared among the groups using the Student's t-test and the Bonfer- roni correction. Significance was established at the level ofp < 0.005.

At the end of the study, the histopathological results for each patient were compared with the ultrasonographically measured endometrial thickness. A cutoff value of 5 mm between a nor- mal and abnormal endometrium was selected to determine the specificity and sensitivity of this method. We prospectively chose to select this measurement because it is the lowest recom-

FIGURE 1. Illustration of measuring endometrial thickness by endo- vaginal sonography.

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mended cutoff value in most of the reported se- ries.6-s

RESULTS

A total of 54 patients complaining of PMB were included in the study. The mean age of the pa- tients was 58 ? 3.2 years. The patients were di- vided into six groups based on the histology re- ports. Pathology reports of insufficient tissue or scant cellular material for diagnosis were consid- ered as atrophic endometrium. The mean endo- metrial thickness and histology for each group are given in Table 1. The thickness of the endo- metrium in each case is presented in Figure 2. There was no statistically significant difference in endometrial thickness between atrophic and proliferative endometria ( p > 0.0051, nor was there any difference among the patients with en- dometrial polyps, hyperplasia, and carcinoma ( p > 0.005). Endometrial thickness in the patients with endometrial polyps, hyperplasia, and carci- noma was significantly greater than that of atro- phic or proliferative endometria ( p < 0.005) (Ta- ble 2).

Histological results of complex or atypical hy- perplasia, endometrial polyp, and carcinoma were regarded as pathological. Cystic hyperplasia, pro- liferative and atrophic endometrium were re- garded as normal. Only one case of atypical hy- perplasia was found in an endometrium with ultrasonographic thickness of 5 mm.

The calculated sensitivity and specificity for the measurement of endometrial thickness as predictors of endometrial pathology were 89% and 83%, respectively.

DISCUSSION

For many years, curettage has been the method of choice for diagnosing endometrial cancer. Be- cause the procedure is not free of complications,

TABLE 1 Measured Endometrial Thickness and Number of Patients

in Each Histopathological Group

Patients Thickness +SD

NO. '/o mm mrn ~

Endometrium Atrophic 30 55.6 4.0 1.9 Proliferative 5 9.2 5.3 2 POWP 7 13 9.2 5.3

Cystic 1 1.8 2.0 Complex or atypical 7 13 10.7 5.5

Carcinoma 4 7.4 12.4 5.3

Hyperplasia

JOURNAL OF CLINICAL ULTRASOUND

ENDOMETRIAL ABNORMALITIES

c - m g 1 0 -

k 7J

u1 = 5 -

30 i

.. .. .. ........ . . . . . . . . ......

..

TABLE 2 Comparison Between Mean Endometrial Thickness of the

Different Groups

Atrophic Proliferative mean i SD mean 2 SD P 3.41 f 3.12 7.2 i 1.7 0.01

POlVP 12.1 ? 5.8 0.000006

Carcinoma 12.0 i 5.04 0.00007 Complex 12.4 ? 7.2 0.00002

Significance = p < 0.005.

and only approximately 10% of women undergo- ing curettage for PMB will be found to have en- dometrial cancer, a noninvasive diagnostic mo- dality has been sought.

Transvaginal ultrasonography enables the ac- curate demonstration of the endometrium. In an attempt to correlate ultrasonographic with histo- pathological findings, endometrial thickness was selected as the variable for excluding endometrial abnormality.

Nasri et a16 could not find any abnormality in patients with ultrasonographic endometrial thickness of 6 5 mm in 59 patients with PMB and chose 5 mm to be the cutoff value. In a pilot study, Goldstein et a17 could not find any abnormality in 11 patients with an endometrial thickness of ~5 mm. Granberg et a18 found no histopathological abnormality if the endometrium was <6 mm, and thus chose a cutoff value of 5 mm. They calculated that using this cutoff value, 70% of the curettages performed could have been avoided.

We chose a cutoff value of 5 mm because most of the reports in the literature refer to this

In contrast to the above reports, the cut- off value of 5 mm in the present series was pre- determined; therefore, the validity of this mea- sure could be studied prospectively. We found that a cutoff measurement of 5 mm yield a sensi- tivity of 89%, and specificity of 83%. This rela-

VOL. 24, NO. 2, FEBRUARY 1996

tively low specificity was due to the fact that pro- liferative endometria was regarded as a normal finding.

Since in most series6-'' a proliferative endo- metrium was regarded as normal, it was not in- cluded in the pathology group. We feel, however, that it is quite impossible to differentiate between hyperplasia and proliferative endometrium by means of ultrasonography alone. This opinion is also shared by others." In our series, 1 of 4 pa- tients (25%) with a proliferative endometrium had an endometrial thickness of <5 mm. Consid- ering hyperplasia a pathological finding would have lowered the sensitivity to 87% but would have increased the specificity to 94%.

Two of our patients (6.6%) with atrophic en- dometria had an endometrial thickness of >5 mm. Granberg et a18 examined 30 patients on es- trogen replacement therapy and found 5 (17%) with an endometrial thickness of >5 mm and a histological diagnosis of atrophic endometria. In a group of 127 women with benign histologic re- sults who had not been receiving estrogen ther- apy, the same authors reported only 2 (1.5%) cases with an endometrial thickness of >5 mm. A similar rate was reported by Osmers et al.' Gold- stein et a17 found two patients (11%) of 17 to have an endometrial thickness >5 mm whose pathol- ogy reports revealed tissue insufficient for diag- nosis. The possibility of such a discrepancy should always be considered, and it should not be attrib- uted merely to inadequate performance of the cu- rettage.

Although the sensitivity in the present series was high (89%), it must be noted that there was a finding of a 1AG1 endometrial carcinoma at an endometrial thickness of 6 mm and atypical hy- perplasia at an endometrial thickness of 5 mm. There were no other ultrasonographic findings that could have suggested an abnormality in ei- ther case. As a difference of 1 mm can be within the limits of the interobserver variation, we feel that these findings may constitute a cause for concern.

Osmers et a19 examined 103 women with post- menopausal bleeding. In an observation study, they concluded that all cases of endometrial pa- thology, including cancer and hyperplasia (com- plex and atypical), were associated with an endo- metrial thickness of 24 mm. They suggested that women with an endometrial thickness of 34 mm should undergo curettage and 3 months later, re- peated sonography. Patients with an endometrial thickness of 2 mm to 3 mm can avoid curettage and should be followed-up by sonography alone. Due to the small size of our series, we hesitate to

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draw definite conclusions from our results. We believe that at this point the role of vaginal so- nography as an aid in determining which women with PMB should undergo curettage has yet to be determined. Therefore, until a further prospec- tive study on a larger series is performed, this method should be reserved for investigational purposes.

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