Transvaginal ultrasonography of the endometrium in women with postmenopausal bleeding: Is it always necessary to perform an endometrial biopsy?

OBJECTIVE: This study was undertaken to evaluate whether it was possible to abstain from performing an endometrial biopsy when endometrial thickness a ccording to transvaginal ultrasonography was less than or equal to 4 mm in women with postmenopausal bleeding or irregular bleeding during hormone rep lacement therapy. STUDY DESIGN: Transvaginal ultrasonography was performed in 361 women aged greater than or equal to 50 years who were referred because of postmenopaus al bleeding or irregular bleeding during hormone replacement therapy. If en dometrial thickness was less than or equal to 4 mm, a Papanicolaou cervical smear was performed and the woman was reexamined with transvaginal ultraso nography after 4 and 12 months. Subjects were also instructed to return if they had recurrent bleeding, in which case transvaginal ultrasonography was performed and an endometrial biopsy specimen was obtained. Women with an e ndometrial thickness greater than or equal to 5 mm underwent either curetta ge or endometrial biopsy. RESULTS: One hundred sixty-three women had an endometrial thickness less th an or equal to 4 mm. In this group one endometrial cancer that was missed b y ultrasonography was diagnosed by cervical cytologic examination and two a dnexal malignancies were diagnosed by ultrasonography. Endometrial malignan cy was diagnosed in 0.6% of the women with an endometrial thickness less th an or equal to 4 mm. Endometrial biopsy was performed because of recurrent bleeding in 6.1% of cases and because of endometrial thickening in 8.1%. No cancer or hyperplasia was subsequently diagnosed among the women with an e ndometrial thickness less than or equal to 4 mm. Endometrial cancer was dia gnosed in 18.7% of the women with an endometrial thickness greater than or equal to 5 mm. The corresponding figure when atypical hyperplasia and endom etrial metastases were included was 20.2%. CONCLUSION: If the false-negative rate of endometrial biopsy techniques is taken into account, then the combination of transvaginal ultrasonography an d cervical cytologic examination is an adequate form of management for wome n with postmenopausal bleeding or irregular bleeding during hormone replace ment therapy as long as endometrial thickness is less than or equal to 4 mm . A randomized prospective study is necessary to verify this finding.