VOL 47: JUNE • JUIN 2001❖Canadian Family Physician•Le Médecin de famille canadien 1193
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Endovaginal ultrasound to exclude endometrial cancer and other endometrial abnormalities.
JAMA 1998;280(17):1510-7.
Research question
Should we still be screening patients with post- menopausal bleeding using endometrial sampling now that endovaginal ultrasound (EVUS) is available?
Type of article and design Meta-analysis by two reviewers.
Relevance to family physicians
Family physicians often see patients with post- menopausal bleeding. Researchers estimate that 3500 women in Canada1 and 36 100 women in the United States2will be newly diagnosed with endometrial can- cer this year.
Until endometrial biopsy became available and was tested in the 1980s, diagnosis was made by uterine dila- tion and curettage (D & C). Endometrial biopsy was found to be less accurate than D & C in 20% of cases if the lesion was focal3and was associated with pain.4The false-negative rate for endometrial biopsy was 2% to 6%.
Many patients star ted on hormone replacement therapy (HRT) will have abnormal bleeding patterns and must be screened for endometrial cancer.5 Endovaginal ultrasound, a newer method of screening these patients, causes less pain than biopsy and will often allow you to reassure patients without obtaining tissue by sampling or D & C.6This article reviews the sensitivity of EVUS for screening these patients.
Over view of study and outcomes The study reviewed the literature from 1966 to 1996. Only prospec- tive studies that evaluated EVUS before endometrial tissue was obtained were selected indepen- dently and reviewed by two reviewers. The reviewers exclud- ed studies that were retrospective, that pooled premenopausal and postmenopausal patients, and that
measured endometrial tissue thickness after biopsy.
Thirty-five studies met the inclusion criteria; 14 were non-English language.
Three outcomes were considered in the pooled data:
cancer, benign endometrial abnormalities (atypical and complex hyperplasia and polyps), and normal. The HRT status of subjects was recorded. Cases with cervi- cal disease were excluded from data review. The authors abstracted and recorded the number of true- positive, false-positive, true-negative, and false-negative cases using reported thickness measurements of 3 to 10 mm.
For each study reviewed, sensitivity, specificity, and exact 95% confidence intervals (CI) were calculated for all EVUS measurements. The authors calculated mean weighted pooled estimates of sensitivity and specificity for each threshold, for any endometrial disease, and for cancer alone.
Results
Endovaginal ultrasound was better at detecting cancer than it was at detecting polyps or hyperplasia. Mean endometrial thickness was 4 mm for women with nor- mal histology, 10 mm for women with endometrial polyps, 14 mm for women with hyperplasia, and 20 mm for women with cancer. At a 5-mm threshold, 96% (95%
CI, 94% to 98%) of women with cancer and 92% (95% CI, 90% to 93%) of women with endometrial disease had abnormal EVUS results. Endovaginal ultrasonography was equally accurate at identifying women with endometrial disease, regardless of HRT status.
For all thickness thresholds tested, specificity was better among women who did not use HRT. At 5-mm thickness, among women with normal histologic find- ings, 23% (95% CI, 21% to 25%) using HRT, but only 8% (95% CI, 6% to 10%) not using HR T, had abnormal EVUS results.
Positive and negative likeli- hood ratios and risk of endometri- al abnormalities were calculated.
At a 5-mm threshold, women with a 10% pretest probability of endometrial disease had a 1% risk
Dr Holten is Residency Director of the Clinton Memorial Hospital Family Practice Residency in Wilmington, Ohio, and an Associate Clinical Professor at the University of Cincinnati College of Medicine. He recently visited the University of Toronto to study evidence-based medicine as it pertains to residency education.
Endometrial sampling for postmenopausal bleeding
Should we put the sampling tools away?
Keith B. Holten,MD
Critical Appraisal reviews important articles in the literature relevant to family physicians.
Reviews are by family physicians, not experts on the topics. They assess not only the strength of the studies but the “bottom line” clinical impor- tance for family practice. We invite you to com- ment on the reviews, suggest articles for review, or become a reviewer. Contact Coordinator Michael Evans by e-mail michael.evans@
utoronto.caor by fax (416) 603-5821
1194 Canadian Family Physician•Le Médecin de famille canadien❖VOL 47: JUNE • JUIN 2001
critical appraisal ❖évaluation critique
of disease if EVUS results were normal and a 57% risk of disease if EVUS results were abnormal. Negative likelihood ratios (probability of disease after negative EVUS results) were approximately 0.1 regardless of use of HRT.
Analysis of methodology
There were no significant weaknesses in study meth- ods or analysis. Because the authors do not provide rules for estimating pretest probabilities of endometrial disease, posttest probabilities have less practical mean- ing. Differences in results between the two reviewers were not discussed. We were not told the location of the studies, so the applicability to family practice offices is unclear. Women taking tamoxifen were excluded, so we do not know whether these results apply to them.
Application to clinical practice
Endovaginal ultrasound is a sensitive test for detecting endometrial disease. With a 5-mm cutoff, sensitivity for detecting endometrial disease and cancer was 92% and 96%, respectively. This high sensitivity makes EVUS an excellent noninvasive test for determining which women with vaginal bleeding do not require biopsy or D & C. Since the false-negative rate of 8% is similar to that of endometrial biopsy, patients with abnormal EVUS results should be referred for D & C.
Bottom line
• Endovaginal ultrasound is noninvasive and can replace endometrial biopsy in your office.
• Postmenopausal patients with abnormal endometrial thickness (≥5 mm) should be referred for D & C.
• Endometrial biopsy has similar rates of false-negative results and can still be used if patients prefer, but abnor- mal histology would still require referral.
• Clinicians can use EVUS or endometrial biopsy inter- changeably when patients present with postmenopausal bleeding.
References
1. National Cancer Institute of Canada. Canadian cancer statistics 2000. Toronto, Ont:
National Cancer Institute of Canada; 2000.
2. Cancer statistics 2000. Cancer J Clin 2000;50(1):12-3.
3. Guido RS, Kanbour AGJ, Ruhn M. Pipelle endometrial sampling sensitivity in the detection of endometrial cancer. J Reprod Med 1995;40:550-5.
4. Stovall TG, Photopulos GJ, Poston WM. Pipelle endometrial sampling in patients with known endometrial carcinoma. Obstet Gynecol 1991;77:954-6.
5. Nand SL, Webster MA, Baber R. Bleeding pattern and endometrial changes during continuous combined hormone replacement therapy. Obstet Gynecol 1998;91:678-84.
6. Lerner JP, Timor-Tritsch IE, Monteagudo A. Use of transvaginal sonography in the evaluation of endometrial hyperplasia and carcinoma. Obstet Gynecol Surv 1999;51(12):718-25.
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Points saillants
• L’échographie endovaginale est une intervention non invasive et peut se substituer à la biopsie de l’endo- mètre dans votre cabinet.
• Les patientes postménopausiques qui présentent un épaississement anormal de l’endomètre (≥5 mm) devraient être aiguillées vers une inter vention de curetage.
• La biopsie de l’endomètre compor te des taux de résultats faux-négatifs semblables et peut quand même être utilisée chez les femmes qui le préfèrent, mais une histologie anormale exigerait quand même un aiguillage.
• Les cliniciens peuvent avoir recours autant à l’échographie endovaginale qu’à la biopsie de l’endomètre lorsque les patientes consultent pour des saignements postménopausiques.
