GYNECOLOGIC ONCOLOGY 43, 217-219 (1991) Endometrial Carcinoma: Transvaginal Ultrasonography Prediction of Depth of Myometrial Invasion VICKEN SAHAKIAN, M.D., CRAIG SYROP, M.D., AND DEBORAH TURNER, M.D. Department of Obstetrics and Gynecology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242 Received March 11, 1991 Myometrial invasion greater than 33% negatively affects the prognosis of endometrialcarcinoma. Since the endometriumis readily differentiatedfrom myometrium via high-resolution trans- vaginal sonography (TVS), this prospective study wasundertaken to evaluate the efficacy of TVS in determiningthe depth of my- ometrial invasion in womenwith endometrialadenocarcinoma. Eighteen subjects underwent TVS utilizing 5.0- and 75MHz probes by a singleexaminer blinded to stageand grade of ad- enocarcinoma. Predicted TVS ratios were categorized as <33% or 233% and compared to actual histologic invasion. Ultrasound predictedthat TVS ratios ~33% are significantly associated with deep (>33%) histologic invasion(P < 0.01, Fisher’s test). When histologic invasion was %33%,TVS was 100% accuratewith no false negatives. The two cases in which TVS ratios erroneously indicated invasion ~33% contained adenomyosis and leiomy- omas. TVS is a highly accurate and convenient methodfor pre- operatively evaluating myometrial invasion. Potentially this evaluation could influence the selection of therapy for poor- surgical-risk candidates or direct appropriate referral of pa- tients with deeperinvasion to a gynecologiconcologist. D1991 Academic Press, Inc. INTRODUCTION Endometrial carcinoma is the most common malig- nancy of the female genital tract. Myometrial invasion greater than 33% negatively affects the prognosis of en- dometrial carcinoma. Recently, staging for corpus cancer has been revised by the Oncology Committee of the In- ternational Federation of Gynecology and Obstetrics (FIGO) to include depth of invasion [l]. Tumors with greater than superficial myometrial invasion are associ- ated with a higher incidence of lymphatic spread and a poorer prognosis [2-41. In grade 1 and 2 tumors, dissec- tion and sampling of pelvic and para-aortic lymph nodes are not necessary if myometrial invasion is less than one- third, since nodal metastasis is only rarely present. These patients can primarily be treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy. Ex- ternal irradiation to the whole pelvis may be indicated for grade 3 tumors or with greater than one-third my- ometrial involvement [5,6]. Transvaginal ultrasonography has become an essential diagnostic aid in the field of gynecology. Sonographic evaluation of the endometrium enables the identification of many histopathologic entities [7,8]. Since the endo- metrium is readily differentiated from the myometrium via high-resolution transvaginal sonography (TVS), this prospective study was undertaken to evaluate the efficacy of TVS in determining the depth of myometrial invasion in women with adenocarcinoma. MATERIALS AND METHODS From January to May 1990, 18 patients with histolog- ically proven endometrial adenocarcinoma referred to the Gynecologic Oncology Division at the University of Iowa Hospitals and Clinics consented to participate in the study. All participants were candidates for surgical therapy. Prior to their surgery, all patients underwent a trans- vaginal ultrasonographic evaluation by a single examiner (C.S.) blinded to the tumor grade or clinical examination. A General Electric RT 3600 (Milwaukee, WI) ultrasound machine with high-resolution 5.0- and 7.5MHz trans- ducers was used. The uterus and endometrium were vis- ualized in longitudinal and transverse planes. For this study, the uterus was also systematically scanned for other incidental findings, such as leiomyomas or adenomyosis. A 5.0-MHz vaginal transducer was used to scan the ad- nexa. The irregular echogenicity of the endometrial tumor was identified and myometrial thickness was measured as the distance from the endometrial-myometrial interface to the serosal edge. Myometrial invasion was measured from the same echogenic interface to the deepest edge 217 C090-8258/91 $1.50 Copyright 0 1991 by Academic Press, Inc. All rights of reproduction in any form reserved.