Errors in the measurement of endometrial depth using transvaginal sonography in postmenopausal women on tamoxifen: random error is reduced using saline instillation sonography

The ATAC (‘Arimidex’, Tamoxifen, Alone or in Combination) adjuvant breast cancer trial: baseline endometrial sub-protocol data on the effectiveness of transvaginal ultrasonography and diagnostic hysteroscopy

BACKGROUND

The 'Arimidex', Tamoxifen, Alone or in Combination (ATAC) trial is a randomized, double-blind trial comparing anastrozole ('Arimidex'), alone or in combination with tamoxifen, relative to tamoxifen alone as 5 year adjuvant treatment for post-menopausal women with early breast cancer. Since tamoxifen is associated with endometrial pathology, the ATAC endometrial sub-protocol was initiated to establish the background prevalence of intrauterine pathology, and to assess prospectively the incidence and nature of intrauterine changes following endocrine therapy. Another aim was to provide data from which advice could be generated on the best endometrium screening method for patients receiving tamoxifen.

METHODS

Patients underwent endometrial assessments at entry to the sub-protocol. The baseline investigations comprised transvaginal ultrasound scanning (TVUS), a hysteroscopy and an endometrial biopsy.

RESULTS

A total of 285 gynaecologically asymptomatic women from 31 centres in 10 countries entered the endometrial sub-protocol. The mean uterine volume was 47.7 cm3. The median endometrial thickness overall was 3 mm. Twenty-four histologically confirmed, pathological changes were observed. Twenty-three pathologies were confirmed by TVUS, and 21 were identified by hysteroscopy and confirmed by histopathology. Women with or without intrauterine pathology had median endometrial thickness of 5 and 3 mm respectively.

CONCLUSIONS

The presence of pathology was associated with increased endometrial thickness. The relative sensitivity and specificity of hysteroscopy and endometrial thickness for the diagnosis of endometrial pathology was comparable to other studies. If screening of the endometrium prior to treatment is appropriate, this study supports the use of an endometrial thickness of 3 mm, as assessed by TVUS, as a threshold for needing further investigation. This study demonstrates that if the endometrial thickness is >3 mm, hysteroscopy and biopsy is the optimal method of detecting intrauterine pathology in women with breast cancer who are about to commence endocrine treatment.

Prospective longitudinal study of ultrasound screening for endometrial abnormalities in women with breast cancer receiving tamoxifen

OBJECTIVE

The goal of this work was to study the role of transvaginal ultrasonography (TVUS) together with colorflow Doppler imaging (CFDI) in the detection of significant endometrial abnormalities induced by tamoxifen.

METHODS

Over a 6-year period, 304 women on tamoxifen as adjuvant therapy for breast cancer were recruited into the current study. Standard demographic data as well as duration of tamoxifen use were collected. Patients were assessed at study entry and at yearly intervals with TVUS together with CFDI. All patients had an endometrial biopsy at the time of study entry, and repeat endometrial evaluations were done subsequently only if there were abnormal ultrasound findings or the presence of irregular vaginal bleeding. All ultrasonic characteristics and Doppler flow measurements were recorded. Descriptive statistics were used to describe the study group. Logistic regression was used to identify significant treatment- and ultrasound-related factors associated with the presence of significant uterine pathology.

RESULTS

One thousand and sixty-one ultrasound assessments were performed on 304 patients over a 6-year period. The mean age was 52.33 (range, 29-79). Seventy-two percent of the patients were postmenopausal at the time of breast cancer diagnosis. The median concentrations of estrogen and progesterone receptor were 75 and 73 fmol/L, respectively. Fifty-eight percent of the patients had received cytotoxic chemotherapy. The mean duration of tamoxifen use was 48.2 months. Thirty-two percent of the ultrasound examinations had associated significant uterine pathology defined as conditions that required further medical or surgical investigation and treatment. However, 80% of the abnormalities represented benign polyps. Six cases of primary endometrial cancer were detected. All cases presented with irregular bleeding. No recurrence of disease was detected at a median follow-up of 48 months. One case of metastatic breast cancer to the uterus was encountered. By setting the endometrial thickness cutoff at more than 9 mm to represent significant abnormality in this patient population, the sensitivity was 63.3%, specificity was 60.4%, positive predictive value was 43.3%, and negative predictive value was 77.5%. To detect endometrial cancer, the endometrial thickness cutoff at 9 mm had a positive predictive value of only 1.4%. Logistic regression analysis showed only endometrial thickness greater than 9 mm (OR 3.99, CI = 1.26-12.65, P = 0.018) and spiral artery pulsatility index measurement (OR 4.18, CI = 1.25-13.92, P = 0.02) to be associated with significant uterine abnormalities.

CONCLUSIONS

Routine sequential ultrasound surveillance in asymptomatic women on tamoxifen is not useful because of its low specificity and positive predictive value. A significant portion of screened asymptomatic women would need to undergo needless surgical evaluations of their endometrium if widespread use of ultrasound is implemented in this patient population.

Transvaginal US and hysterosonography in postmenopausal women with breast cancer receiving tamoxifen: correlation with hysteroscopy and pathologic study

Tamoxifen citrate therapy increases the prevalence of benign and malignant uterine lesions. At transvaginal ultrasonography (US), the finding of a thickened central endometrial complex, with or without cystic changes, is often nonspecific and may be caused by an endometrial polyp, submucosal leiomyoma (fibroid), endometrial hyperplasia, carcinoma, or cystic atrophy. In addition, because of an increased prevalence of adenomyosis or adenomyosis-like changes in women receiving tamoxifen, proper transvaginal US assessment of endometrial thickness and abnormalities is difficult in some women. Hysterosonography, as an adjunct to transvaginal US, allows identification of intracavitary lesions and focal and diffuse endometrial abnormalities and helps determine whether an abnormality is endometrial or subendometrial. Endometrial polyps may be seen at transvaginal US as nonspecific thickening of the endometrial complex, with or without cystic changes. At hysterosonography, they appear as an echogenic mass with smooth margins. Submucosal leiomyomas may protrude into the endometrial cavity, causing false endometrial thickening at transvaginal US. Hysterosonography shows a round structure arising from the myometrium with a thin, overlying endometrium. At transvaginal US, when the endometrium cannot be accurately measured or when there is a nonspecific thickened central endometrial complex, hysterosonography can provide additional information and can help in the triage for hysteroscopic versus nondirected endometrial biopsy. Correlation of transvaginal US and hysterosonographic findings with hysteroscopic and pathologic findings enhances understanding of these changes, as well as the limitations and potential pitfalls of both imaging techniques.

Measurement precision and normal range of endometrial thickness in a postmenopausal population by transvaginal ultrasound

OBJECTIVES

The aim of this study was to examine the endometrial thickness (ET) in an asymptomatic postmenopausal population, and to assess the long-term variability.

DESIGN

A total of 1182 asymptomatic generally healthy postmenopausal women were enrolled into this cross-sectional evaluation of the ET. Measurements were performed by transvaginal ultrasound. A subset of the women (n = 178) was examined twice 3 months to 2 years apart to assess the long-term variability.

RESULTS

Cross-sectionally, ET varied with length of menopause. During the first 5 years after menopause (YSM) the mean ET was 2.3 mm but it decreased by 0.03 mm/year (P < 0.01). From 5 to 13 YSM the ET remained stable at a mean of 1.8 mm with no significant changes (P = 0.13). Thereafter there was a minimal increase of 0.01 mm/year (P < 0.05). In order to minimize the influence of natural changes on ET, only women who had reached the menopause more than 5 years earlier were entered into the subsequent long-term study. The mean ET was 2.0 mm +/- 1.0 mm with no significant differences within or between the observers' measurements. The precision errors were less than 1 mm.

CONCLUSIONS

The normal range of the thickness of the postmenopausal endometrium in asymptomatic women varies with YSM. There is a high long-term agreement within and between observers in measuring the ET.

Saline infusion sonohysterogram as initial investigation of the endometrium and uterine cavity

The results of 54 consecutive saline infusion sonohysterograms (SIS) are presented. Sonohysterogram, in conjunction with Pipelle endometrial sampling, was found to be a reliable and accurate method of initial investigation of the endometrium and uterine cavity with good correlation with other methods of investigation. It was well tolerated in an outpatient setting, saved two out of three of the women from needing a hysteroscopy and curettage, and yielded information beyond that available from hysteroscopy and curettage.

Endometrial evaluation with transvaginal US and hysterosonography in asymptomatic postmenopausal women with breast cancer receiving tamoxifen

PURPOSE

To determine performance characteristics of transvaginal ultrasonography (US) and hysterosonography for diagnosing endometrial abnormality in asymptomatic postmenopausal women with breast cancer receiving tamoxifen.

MATERIALS AND METHODS

The authors prospectively examined 138 women receiving tamoxifen by using transvaginal US, hysterosonography, and office hysteroscopy. The combined hysteroscopic-histopathologic diagnosis was the reference standard. Sensitivity, specificity, positive and negative predictive values, and likelihood ratios of transvaginal US and hysterosonography were calculated.

RESULTS

All 138 women underwent transvaginal US; 104, successful hysterosonography; and 117, successful hysteroscopy. Uterine abnormality was present in 47 (40.2%) of 117 women: 45 with polyps and two with submucosal fibroids. Receiver operating characteristic curve analysis revealed 6 mm to be the optimal endometrial thickness cutoff for diagnosing endometrial abnormalities. When a thickness greater than 6 mm or a focal endometrial finding was considered abnormal, transvaginal US had a sensitivity of 85.1% and a specificity of 55.7%. In 92 women who completed transvaginal US, hysterosonography, and hysteroscopy, hysterosonography was more specific (79.2%; P =.008) but not significantly more sensitive (89.7%; P =.508) than transvaginal US. When women with abnormal transvaginal US findings were further examined with hysterosonography, the sequential combination of transvaginal US and hysterosonography was more specific (77.1%) than transvaginal US alone (P <.001), without a significant decrease in sensitivity (78.7%; P =.25).

CONCLUSION

In asymptomatic postmenopausal women receiving tamoxifen, 6 mm is the optimal endometrial thickness cutoff for diagnosing endometrial abnormalities with transvaginal US. Further examination with hysterosonography can improve specificity by reducing the high false-positive rate of transvaginal US.